TRANSACTIONS OF SECTION C. 



715 



(that then being worked) is 5 feet 3 inches. Three feet helow this is a thinner 

 seam two feet thick. 



At the Irvine liavine the Pierre sliales rest upon the Belly River series. At 

 the bottom of the former is a coal seam, but it is not regular enough to work. 

 These deposits are interesting on account of the reptilian remains which seem 

 common amongst them. 



Those found by the writer have been identified as belonging to the genus Lcelaps, 

 allied to the M^gaJosaunis ; some other remains of a peculiar character are 

 recognised as portions of the carapace of a land turtle of the genus Trionyx. 



The deposits are not very uniform in arrangement; the beds consist of 

 alternations of sandstone and clay ; some of the latter is greenish in tint and contains 

 selenite. 



The following table was given by the writer for comparing the Cretaceous 

 deposits of the north-west, referred to in the paper, with those of the same system 

 in some parts of the United States and Western Europe : — 



In the bed of ironstone nodules, a little higher than the river level, excellent 

 fossils of plants allied to the genus Brasenia were found. 



8. The Disaster at Zug on July 5, 1887. By the Rev. E. Hill, M.A. 



On July 5, 1S87, at the town of Zug, in Switzerland, a portion of the shore 

 gave way and sank into the lake. About three hours later another much larger 

 adjacent area also suddenly subsided, so that in all an area considerably over two 

 acres, with half of one of the principal streets, was submerged to a depth of about 

 20 feet. It can be seen that the subsoilcousistsof coarse gravel and sand, followed 

 after a few feet by soft wet sand and fine mud. According to Professor Heim, this 

 fine mud or sludge reaches to a depth of nearly 200 feet, and the disaster is shown 

 to be due to a flowing out into tlie lake of this mobile sludge from under the 

 superincumbent weight of buildings and firmer ground. The buildings collapsed 

 as they sank. The catastrophe must have been long impending ; the exact cause 

 which precipitated it is indeterminate, but a low level of the lake and tremors from 

 pile-driving for new quays are suggested as contributories. On the English coast 

 the incessant changes of pressure from tides probably render impossible such 

 instability of equilibrium. 



