SMITHSONIAN EXPLORATIONS, I927 29 



Our i)arty remained at ^Milwaukee for a week collecting material 

 and data in the Lake Church and Milwaukee quarries before pro- 

 ceeding into Michigan. Here a camp was established at Charlevoix, 

 from which were explored all localities known to the Michigan Sur- 

 vey and man}' new ones. Owing to the fact that the geology was 

 complicated by local structure and limited exposures, camp was not 

 moved for two weeks. On completion of the work in the vicinity of 

 Little Traverse Bay. the outcrops were traced across the belt to the 

 eastern shore of Michigan. IVIuch of the country is swampy and 

 undeveloped, and traveling is difficult away from the beaten paths of 

 the tourists. From an industrial standpoint the northern belt of 

 Michigan is highly interesting, for it contains several of the largest 

 limestone quarries in the world (fig. 29). Much of the rock is dolo- 

 niitized and it is impossible to produce the fine grades of cement 

 which we find in the New York Portland works ; but a good deal 

 of the material is converted for alkali uses. This entire area is a 

 collector's paradise, for nearly every bed in the section is crowded 

 with excellently preserved fossils in great variety (fig. 30). Fossils 

 are perhaps Ijetter known to the layman in this region than in most 

 districts of the L^nited States, for the gravel of the bathing l)eaches 

 and the shores of Little Traverse Bay (figs, ly and 28) are com- 

 posed of water-worn pebbles of fossil corals and shells, locally 

 called " Petoskey Stones." 



A visit to Silica, Ohio, to obtain a collection of what are probably 

 the finest preserved Devonian fossils ever found, led to a meeting 

 with Dr. J. E. Carman, of Ohio State University. As this fossil 

 fauna has been Dr. Carman's special province of research, a day of 

 collecting and study was very profitably spent with him here. 



On the trip through Ontario to Limestone Mountain. Mich., addi- 

 tional data and collections relating to the Ordovician, Silurian, and 

 Lower Devonian were assembled. Limestone Mountain (fig. 31). 

 near Baraga at the southern end of the Keweenaw Peninsula, is an 

 erosional remnant or monadnock, forming an isolated reminder that 

 this area was below sea level during much of Lower and Middle 

 Palezoic times. 



L^p to within the present decade it was believed by the majority 

 of geological students that the interior of our continent was a region 

 of vast seas which existed with l)ut little change over long lapses of 

 time. Such an inland sea. stretching from eastern New York to 

 Iowa and Alissomi. and from Kentuckv to northern ^Michigan, was 



