166 BULLETIN 109, UNITED STATES NATIONAL MUSEUM. J 



more than a single geological position. " The old Ked Sandstone " 

 in the vicinity of the Porcupine Mountains has been shattered 

 similarly to the limestone at Mackinac Island. 



The limestones bordering Little Traverse Bay are noticed, and tht-* 

 ledge on the south shore is thought to overlie that at the head of 

 the bay. The bituminous shale is again detected " just within Grand 

 Traverse Bay " and is compared with that of Thunder Bay. 



From Grand Traverse Bay to the southern boundary of the State 

 the immediate shore is destitute of outcrops, but he says " this lime- 

 rock comes to the surface in a hilly region lying between Pere Mar- 

 quette and White Rivers at a distance of 10 to 12 miles from the 

 shore of Lake Michigan. These outcrops, mostly in Oceana County, 

 are now known to belong to the Carboniferous limestone. 



Under the head of Tertiary Clays he says that " a large propor- 

 tion of the rocks of the peninsula are overlaid by a series of beds of 

 clay, sand, and gravel that sometimes attain a thickness of several 

 hundred feet." This undoubtedly refers to what we now understand 

 as drift. Doctor Houghton seems, however, to embrace here all the 

 incoherent surface deposits, since he notices particularly' the strati- 

 fied clays upon the lake shores. These, in the vicinity of Detroit, 

 are said to be 118 feet thick, and on Lake Michigan 100 to 400 feet. 

 The glacier theory of the drift was not yet in vogue, the great work 

 of Agassiz not appearing until 1840, and his first enunciations at 

 Neuchatel, in 1837, following Charpentier (18.34), Venetz (1821). 

 and Play fair (1815). 



Dr. Houghton in this report calls attention to beds of shell marl 

 and to deposits of gypsum on the shore of Saginaw Bay, on St. 

 Martins Island near Mackinac, and on the northern Peninsula be- 

 tween Green Bay and Mackinac. He devotes several pages to a 

 statement of facts and traditions bearing on change of level in the 

 waters of the Great Lakes (pp. 20-27). 



Speaking next, of the southern part of the Peninsula, he says, 

 " the whole northern part, at least, of Calhoun County is based upon 

 the sandstone series of the great Carboniferous group of rocks." 

 This statement is noteworthy, since later geologists, after assigning 

 the formation to the Devonian systeui, have returned, on paleonto- 

 logical grounds, to the position which with Doctor Houghton seems 

 to have been almost an inspiration. The clays of Branch Coimty, 

 containing kidney iron ore. he thinks " may probably be referred to 

 one portion of the Carboniferous group, though this connection has 

 not absolutely been shown to exist" (p. 29). Tlie ore he regards 

 as of the " same character as that from which much of the iron of 

 our neighboring State of Ohio is manufactured." The clay is re- 

 garded " as of great value in the manufacture of stoneware" (p. 29). 



