348 REPORT — 1875. 



The first boring was abandoned at the depth then attained (1013 feet), 

 and a second boring was commenced, which has now (August 1875) reached 

 the depth of 1820 feet. This has proved that the Kinuneridge-Clay fauna 

 extends much lower than was inferred from the results of the first boring. 

 Gryphoea {Exogyra) virgula has been met with at various depths down to 

 1656 feet. Ammonites ynutahilis extends from about 960 feet to 1652 feet. 

 RJiynchonella pinyuis is common in some of the lower cores. The presence 

 of these fossils would seem to settle the question as to the age of the beds in 

 which they occur ; but fortunately we are not now left to palaeontological 

 evidence alone. At about 1769 feet an oolitic rock was reached, which con- 

 tinued to 1786 feet, where the beds again changed to shale. The upper part 

 of this 17 feet of rock is rather coarse in grain ; the lower part is finer. Save 

 as regards colour (which depends on weathering) these cores may be matched 

 precisely by examples of Coralline Oolite in the Museum of the Geological 

 Survey at Jermyn Street. Mr. Bristow kindly referred me to the specimens 

 which are contained in 3iV^ all-case No. 46. No. 58 in this case is a rather 

 coarse-grained oolite from Steeple Ashton in Wiltshire, exactly resembling 

 the cores found at about 1770 feet. No. 59 is an oolite of finer grain from 

 Buckland, near Faringdon, which as closely resembles the cores found at 

 about 1782 feet. These rocks are not very fossiliferous ; and in the boring 

 they appear to contain only small oysters, which occur chiefly in the lower 

 part. The coarse oolite in the boring is hard, and takes a fine i^olish ; the 

 finer variety is softer. 



We may, then, with some degree of safety, assume that these rocks repre- 

 sent the Coral Rag (Coralline Oolite). The Upper and Lower Calcareous Grits 

 are either absent, or they are represented by sandy, rather calcareous shales, 

 which do not in any way differ from shales which are abundant in the true 

 Kimmeridge Clay. 



It will perhaps be better to leave the description of the fossils until the 

 materials have been more carefully worked iip and the whole series fully 

 arranged ; it will also be as well to defer till then a detailed section of the 

 strata. Mr. Etheridge has carefully looked over the cores ; and from his 

 notes the foregoing remarks on the fossils are taken. 



ilr. H. Woodward has examined the Crustacea, and he refers some 

 remarkably fine examples, found in the Kimmeridge Clay at 1057 feet, to a 

 new species of Ccdlianassa. He proposes to call this C. isocJiela ; it is the 

 oldest known form of the genus. Fragments of another crustacean were 

 found at the same depth ; Mr. Woodward refers this to Mecochh-us Peytoni, 

 Woodw. 



Beds of sandstone have been met with at various depths in the Kimmeridge 

 Clay. Frequently they are traversed by wavy concretionary lines, which 

 look exactly like fossils on the, outside of the core. AU these sandstones are 

 cemented by carbonate of lime. Oysters are almost the only fossils which 

 they contain. Throughout both borings it has been noticed that oysters are 

 most abundant in the sandy beds. 



The shales are frequently traversed by oblique veins of carbonate of lime. 

 The hole, when not lined, is very apt to fall in at these points. In the 

 method of boring employed by the Diamond Company it is necessary to send 

 a stream of water down the middle of the rods from the surface, the water 

 rising again to the surface outside the rods. Mr. Thornton, the engineer in 

 charge, noticed that the hole fell in much more readilj' after heavy rain, when 

 the brook from which the water was pumped was swollen, than it did when 

 the brook only ran with spring-water. He referred this, no doubt correctly, 



