255 



responsible, as the whole difficulty arises from natural causes, they 

 have expended considerable sums of money in endeavouring to 

 find a remedy. 



Before concluding this part of the subject I will give you an 

 example, though perhaps an exceptional one, of the character of 

 the material on Avhich some houses are standing. Mr. Bolwell put 

 down a boring on his premises in Somerset Buildings, opposite 

 Walcot Church, and passed through 30 to 40 feet of greasy sandy 

 marls, and blocks of sandstone derived from the Yellow Sand 

 above Camden Crescent, and mixed with it a considerable quantity 

 of iron pyrites, brought away by water in its passage over the 

 edges of the upper Lias. 



Paleontology of the Hedgemead Landslip. 



In my notices of the ancient natural history of the Hedgemead 

 beds I shall confine myself entirely to those of the Upper Lias, 

 which first show themselves in a little patch behind Camden 

 Crescent ; the beds below to the top of the Surveyor's shaft not 

 having been touched are necessarily unknown. This well, com- 

 menced in about the middle of the series, was carried down 65 

 feet, where the Upper Lias terminated, resting, as it does in 

 other places, on a somewhat irregularly stratified bouldered series 

 of Marlstone beds of a greyish colour, the thickness of which is 

 uncertain, as the sinking was not continued further. In other 

 districts these Middle Lias upper rocks vary from two to twelve 

 feet. It is precisely the same bed given by myself in a section 

 p. 16 of my paper " On the Middle and Upper Lias of the West 

 of England." 



In my conversations with the Surveyor it was especially im- 

 pressed upon him that his object being to cure the source of evil, 

 which I believed to be from superficial water, the moment his 

 sinking proved itself to be in regularly stratified beds of Marl, 

 which were usually quite impervious to water, the workings 



