REPORT OF THE STATE PALEONTOLOGIST 1901 435 



mite when wet become softened, so that they break freely in 

 any direction. The fossils, however, as everywhere in these 

 rocks, are internal and external casts, and special pains were 

 taken to secure specimens showing the characteristic exterior 

 characters of the organisms. 



On the opposite side of the Grand river are exposures at 

 Hogg's and Webster's quarries, the latter a small opening of 

 the basal layers on Crumby street, which furnished many inter- 

 esting species. Just above the upper bridge on the east bank 

 is a slight, unworked exposure of the upper compact, gray, 

 slabby dolomite, which is profuse in gastropods. Melross's 

 quarry, 1 mile north of the village on the east bank of the 

 river, exposes a yellow dolomite 15 to 20 feet thick, running 

 into a heavy bed toward the top. This rock is full of 

 Megalomus, but good specimens of other fossils are not common, 

 and gastropods less frequently seen. This outcrop lies about 

 2 miles north of Ballantine's quarry and is probably about 50 

 feet higher, completing the section at Gait, which can not be 

 less than 100 feet thick. 



All these outcrops are along the strike of the formation, and 

 Sir William Logan regarded the strata here as representing the 

 middle part of the group, those at Hespeler on the river Spree 

 being in his judgment below this horizon, while the striking 

 natural section at Elora, about the confluence Qf the Grand and 

 Irvine rivers, where the canyon is not less than 100 feet deep, 

 is considered the summit section of the formation. The series 

 of fossils obtained from all these Guelph localities will consti- 

 tute a useful addition to our museum collections. 



Limestones of the Marcellus stage and origin of their faunas. The 

 Marcellus formation is typically represented by a series of black 

 bituminous shales, carrying a fauna which has peculiarities so 

 well marked as to render it readily recognizable. Among these 

 shales there occur in different sections interbedded limestones 

 which are specially noteworthy for the diversity of their organic 

 contents. Thus in eastern sections some 30 feet above the base 

 of the shales lies the series of limestone banks which has been 



