Photographed by TEMPEST ANDERSON, M.D., 17 Stonegate, York.
(Enlargements from 4-plate negatives.)

Report of the Committee, consisting of Mr. G. J. SYMONS, Mr. C. DAVISON (Secretary), Sir F. J. BRAMWELL, Mr. E. A. COWPER, Professor G. H. DARWIN, Professor EWING, Mr. ISAAC ROBERTS, Mr. THOMAS GRAY, Dr. JOHN EVANS, Professors PRESTWICH, HULL, · LEBOUR, MELDOLA, and JUDD, Mr. M. WALTON BROWN, and Mr. J. GLAISHER, appointed to consider the advisability and possibility of establishing in other parts of the country Observations upon the Prevalence of Earth Tremors similar to those now being made in Durham in connection with coal-mine explosions.

DURING the past year the Committee have examined a large number of instruments designed for the observation of earth tremors and other small movements of the earth's crust. They hope to be able, in their next report, to report upon them and to recommend instruments specially adapted for use in this country.

The Committee invite designs or suggestions for the construction of the following instruments: (1) a seismoscope for recording the time of occurrence of a tremor, either by stopping or preferably by not stopping a clock; (2) a self-registering instrument for determining the time of occurrence, the direction, amplitude, &c., of a tremor or series of tremors ; and (3) a simple form of nadirane or other instrument for the observation of slight earth-tilts. Communications on this subject should be addressed to the Secretary (Mr. C. Davison, 38 Charlotte Road, Birmingham), who will be glad to answer any inquiries.

The Committee respectfully suggest that they be reappointed, but ask for no grant.

Report of the Committee, consisting of Dr. H. WOODWARD (Chairman), Messrs. W. D. CRICK, T. G. GEORGE, Wм. HULL, E. A. WA WALFORD, E. WILSON, H. B. WOODWARD, and BEEBY THOMPSON (Secretary), to work the very Fossiliferous Transition Bed between the Middle and Upper Lias in Northamptonshire, in order to obtain a more clear idea of its fauna, and to fix the position of certain species of fossil fish, and more fully investigate the horizon on which they occur. (Drawn up by the Secretary.)

IN 1863 Mr. E. C. H. Day published in the 'Journal of the Geological Society' a paper entitled On the Middle and Upper Lias of the Dorsetshire Coast.' In this paper, page 293 of the Journal, Mr. Day describes 'The Marlstone with its Pleurotomaria Bed.' From this description it appears that the marlstone rock bed is capped by a remarkable bed of small thickness, abounding in gasteropods and other fossils, which indicate -particularly the ammonites-a passage bed between the Middle and Upper Lias. Mr. Day considers that the Fish bed of Ilminster and Dumbleton is absent.

In 1865–66 Mr. Charles Moore published, in the 'Proceedings of the Somersetshire Archæological and Natural History Society,' a long paper 'On the Middle and Upper Lias of the South-West of England,' in which he describes a zone situated between the Marlstone and Fish bed under the name of the Leptona beds.

In 1872 Mr. Thos. Beesley read a paper before the Warwickshire Naturalists and Archæologists' Field Club entitled 'A Sketch of the Geology of the Neighbourhood of Banbury,' in which mention was made of a passage bed between the Middle and Upper Lias. This paper was published in the Proceedings' of the Society.

·

In 1876 Messrs. Tate and Blake published their Yorkshire Lias,' in which they described a zone of the Middle Lias, under the name of the Zone of Ammonites Annulatus, occupying the position of the Pleuroomaria bed of Day and the Leptana beds of Moore.

Again, in 1879 Mr. Edwin A. Walford published in the 'Proceedings of the Warwickshire Naturalists and Archaeologists' Field Club' a paper 'On Some Middle and Upper Lias Beds in the Neighbourhood of Banbury.' This paper describes a bed situated between the Marlstone rock bed and the Upper Lias Fish bed, in the south-western parts of Northamptonshire, under the name of the Transition bed.

Some few years ago two of the members of this committee-Messrs. Thompson and Crick-detected the same bed in a rather large number of widely separated parts of Northamptonshire, and as far north as Tilton, in Leicestershire.1

As it seemed of considerable interest to more thoroughly investigate this bed and those immediately above and below it, and there was much difficulty in doing so owing to nearly all the Marlstone quarries being closed, the British Association kindly made a grant of money for the purpose. The present report gives the results of the investigation.

Mr. E. Wilson had previously described the deposits at Tilton, but did not separate the Transition bed from the rock bed.

By the date of delivering the report, July 25, it has not been possible to thoroughly investigate all the material collected, but if anything further of interest is found a supplementary report will be presented in 1892.

We particularly desire to thank Mr. S. S. Buckman, F.G.S., for examining and reporting on the ammonites, and Mr. E. Wilson, F.G.S., the gasteropods.

SITUATION OF SECTIONS.

The sections that have been opened are situated respectively at Milton, about 3 miles S.S.W. of Northampton; at Bugbrook, about 4 miles almost due west from the last named; near to Arbury Hill, and at Catesby, about 8 miles further westward; and at Chipping Warden, about 6 miles S.S.W. of the Arbury Hill one.

The list of fossils contains some collected over a rather wider area and extending northwards as far as Watford (on the railway), 71⁄2 miles N.E. of Catesby.

It will be noticed, therefore, that the investigation embraces places situated 14 miles apart from N.E. to S.W., and about 12 miles at right angles to this.

GENERAL SECTION.

The section given below shows the sequence of the beds studied, in its most complete form.

'Communis'

Unfossiliferous clays of the Upper Lias

A. Upper Cephalopoda bed

beds. B. Clay with numerous small planulate ammonites 'Serpentinus' ƒ C. Lower Cephalopoda bed

'Spinatus' zone. M. Marlstone rock bed

Ft. in. 70 to 100 0 0 6

3 to 6 0

0 6 to 9

3 to 5 0

0 4

0

0 4

0 2

05

O greatest thickness.

6 0

In regard to the above section we may say that there is no exposure giving the full sequence, and that where the upper beds are shown the lower ones may differ somewhat from this, and vice versa.

With regard to E and F the evidence is about equally balanced as to whether they should go with the Serpentinus' beds or the Fish beds, and so we prefer at present to leave it undecided. They may be regarded as constituting a transitional zone.

The first section was opened in the spring of 1890 at Milton, about 3 miles S.S.W. of Northampton, but owing to the delay in procuring permission, and other difficulties experienced, that was the only one that could be opened that year. In some respects, however, this was the most interesting section examined. It has the advantage of being further eastward than any other section exposing the same beds, and, as has been pointed out elsewhere,' the beds seem to vary more at right angles to the line of strike than they do along it.

The Middle Lias of Northamptonshire, by Beeby Thompson, F.C.S., F.G.S.

SECTION OF MIDDLE AND UPPER LIAS BEDS NEAR TO MILTON.

The letters A, B, C, &c., refer to the position of beds in general

section.

Ft. in.

1. Soil passing into marly clay. The clay, which is
nearly white, only occupies a few inches near the
base. A few fragments of Belemnites. .. 26
E.-2. CEPHALOPODA BED.-An argillaceous limestone,
hard, nearly white, very fossiliferous, chiefly large
ammonites of the falcifer group badly preserved.
Ammonites serpentinus (near to)

Aptychi.

F.-3. A light-coloured, somewhat shaly bed, moderately
hard, scarcely to be distinguished from No. 2 in
appearance, and containing similar Ammonites of
large size. Numerous fish fragments in lower
portion

04

. 0 4

G.-4. FISH BED.-A light-coloured nodular limestone, not
continuous, resting on or in thin shale. Fish
fragments common, also small Ammonites and their
aptychi.

H.-5. PAPER SHALE.-A shale splitting into very thin
laminæ, of a colour almost exactly like No. 3.
Fish fragments common

I.-6. FISH BED in large slabs, most of which split easily
into two or three thinner ones. Fewer fish frag-
ments and other fossils in this than in No. 4

J.-7. PAPER SHALE changing downwards into a more
clayey layer, and then a more sandy one, altering
to a reddish colour, and gradually losing its shaly
character

8. Bluish shale or clay, somewhat sandy, very thin, but
quite distinct and continuous throughout the sec-
tion. Less regular in a horizontal direction than
the other beds

TRANSITION BEDS.

K.-9. Red sandy layer with a few badly preserved fossils,
chiefly Belemnites.

. 0 2

0 4

0 2

. 0 5

L.-10. Grey marl, or limestone, not very distinctly sepa-
rable from the sand above or the limestone below.
A great many Belemnites, perhaps six or seven
species, but much worn and often fragmentary.
Gasteropods less abundant here than in most
places where the same bed is found
Ammonites acutus (many)

. 0 5

. 07 Arcomya vetusta (many). Holandrei (many) Lima punctata.

Astarte (two species).

Rhynchonella (many).

Gasteropods, &c.

M.-11. ROCK BED OF MIDDLE LIAS, very fissile at the top,
upper surface very like, and has on it similar
fossils to the Transition bed proper. Many small
flat pebbles, probably quite local, and fair amount
of crystallised carbonate of lime at the junction.

With regard to this section it may be observed that in no other locality in the county have we found the Fish bed so distinctly separated into two layers.

SECTION AT BUGBROOK.

(Mr. Ward's farm, near the village, and south of the railway.)

B.-1. Soil and blue clay, much disturbed, many little
planulate Ammonites lying about on the weathered
surface

C.-2. LOWER CEPHALOPODA BED.-An irregular layer of
small water-worn stones of a ruddy yellow colour.
Oolitic in places, the broken surface across these
oolitic parts looking very like coral

Ammonites communis?

Nucula Hammeri.

Nautilus, &c.

D.-3. Blue clay, rather darker colour than usually met
with on this horizon, red and sandy at the top,
also very ruddy and shaly towards the bottom.
Few fossils

Ft. in.

3 0

. 0 6

4 6

E and F.-4. CEPHALOPODA BED (INCONSTANT BED).-A hard
bluish grey stone, weathering quite red at joints
and exposed surfaces-called 'Pendle' by the
workmen. Many Ammonites of the falcifer group
and very few of the planulate, the former often
crushed quite flat, as they are in the shales below 0 8
Nautilus astacoides? large and small.

The fine ribbed variety of A. Strangwaysi seems
most often crushed.

H.-5. PAPER SHALE.-A grey, finely laminated shale,
weathering to a much lighter colour, containing
fish fragments and a good number of flattened
Ammonites--chiefly the fine ribbed variety of A.
Strangwaysi

I.-6. FISH BED.—A bluish-grey stone, laminated like the
shales, and weathering quite white on the exterior.
Comes out in large flat slabs-only nodular in one
part, and that just over a large fissure in the rock
bed below

Fish fragments fairly abundant, only small Ammonites,
chiefly A. latescens.

Saurian remains more abundant here than elsewhere
in the same bed.

J.-7. PAPER SHALE like No. 5, though fewer Ammonites
probably

L-8. TRANSITION BED.-Not present as a distinct bed,
and no red clay; nevertheless clearly shown by the
altered character of the top of the rock bed, and
by the presence in this of Ammonites Holandrei,
Cerithium ferreum, small Rhynchonellæ, &c.

Nearly as hard as the rock bed itself.
No pebbles here.

04

. 0 2

1891.

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