58 Report— 1842. 



of sand in holes formed by the rise of bubbles of air from a subjacent bed of clay. 

 Dr. Buckland suggested that some of the cavities, and casts of cavities, on beds of 

 sandstone at Storton Hill, near Liverpool, and also near Shrewsbury, which have 

 been attributed to rain-drops, may have been due to the extrication of air-bubbles ; 

 care would therefore be necessary to distinguish between these two causes of phee- 

 nomena, which have hitherto been exclusively attributed to rain. 



On lite Discovery of Lnsects in the Lower Beds of Lias of Gloucestershire. 

 By the Rev. P. B. Brodie. 



Such fossils being comparatively of great variety, and with one exception not ha- 

 ving been before discovered in the lias, the author was unwilling to delay any notice 

 of the occurrence of these organic remains in the lowest member of our oolitic series. 

 His former discovery of insects in the Wealden led him to a closer investigation of the 

 strata in the neighbourhood of Cheltenham, and the result has proved highly satisfac- 

 tory. He has already detected elytra of one or more genera of Coleoptera, one or 

 two minute beetles, and a few wings of some insects, one of which resembles that of 

 the Libellula. The above fossils are generally of small size ; the largest elytron is a 

 little more than half an inch long, and the largest wing about an inch in length ; nor 

 are they by any means abundant. 



The beds in which they occur consist of thin courses of blue, green and white 

 limestone, forming some of the lower beds of the lias formation, so extensively deve- 

 loped in the neighbourhood of Cheltenham and Gloucester. 



Notices of the Geology of Derbyshire and Neighbouring Counties. By 

 Elias Hall. 



In illustration of this communication Mr. Hall presented models, maps and sections 

 on a large scale. 



A skull which had been found in excavating a lock at the east end of the Forth 

 and Clyde Canal, on the Firth of Forth, at twenty feet below high-water mark, was 

 placed on the table. It belonged probably to the domestic breed of cattle. 



On tlie Structure and Mode of Formation of Glaciers. By James Stark, 

 M.D., F.R.S.E. 



Dr. Stark presented his views on the stratified structures occurring in glaciers under 

 the following heads : — 



1. On the Occurrence and Mode of Formation of Horizontal Strata: — Most writers 

 seem to be agreed that these horizontal layers mark the additions which had been 

 annually made to the glacier, each layer being the accumulated snows which fell 

 during one year. Dr. Stark however showed, from a reference to the meteorological 

 tables kept at the Hospice of the Great St. Bernard, that considerable doubts might 

 be entertained as to this being the case. These layers of ice are in general from 1 foot 

 to 3 feet in thickness, but the tables demonstrate that from 300 to 700 inches of 

 snow fall during the six winter months alone, i. e. from October to March inclusive. 

 Dr. Stark therefore thought it was quite possible that each horizontal layer denoted 

 the separate storms or falls of snow, or if they marked the annual accumulations, 

 apparently proved, what had not previously been suspected, that snow and ice waste 

 nearly as rapidly in the upper as in the lower regions. 



2. On the Occurrence and Mode of Formation of Longitudinal and Vertical Strata. — 

 Respecting the structure to which he referred the lamellar, banded, striated or rib- 

 boned structure, mentioned by different observers, Dr. Stark offered the following 

 explanation : — Late researches show that glaciers advance at the rate of from 200 to 

 500 or 600 feet annually, and as it is generally allowed that this takes place only 

 during the spring and summer months, the daily progression of the glacier must be 

 from 1^ to 3 feet. This daily movement extends more or less to the whole extent 



