WHITTEMOKE ON LIMESTONE EXPOSURE, GKAND RAPIDS. 63 



ment, as it answers the acid test, lias beeu biu-ued for lime, and is identi- 

 fied by means of fossils which will be mentioned later. 



On "the the east side of the river the same rock was found in the exca- 

 vations for Sweet's Hotel, but it had many holes through it. The same 

 feature was seen in digging for the foundations for the National City 

 Bank building. At Mr. Power's well, in the Arcade, just north of Pear 

 street, the lime rock was found li feet thick under 6 or 8 feet of drift. 

 These features indicate the southern edge of the formation, as shown on 

 the map. In the west side canal bedrock was struck at a little more than 

 100 feet south of the dam. Away from the river the limerock was not 

 found south of Bridge street, its boundaries, however, I do not know. 

 The ridge is found in the river bed at a point near the Kent Furniture 

 Go's shops, and slopes rapidly to the north. The apparent dip, as seen in 

 the river bed, is to the south, but the true dip is N. E. by E.* Such must 

 evidently be the case in order that the strata may pass under the coal 

 measures of the center of the State. The upper line on the west side runs 

 a little north of west, but has not been determined. 



To Hon. \Vm. T. Powers I am indebted for much valuable information 

 concerning this outcrop. 



The thickness of the rock at the head of the rapids is 52 feet. It is 

 found under a drift deposit of two or three feet and in some places is 

 covered only by the sod. The same kind of limestone, with the same 

 crystals, is found at Kellogsville^ six miles south of the city. 



The strata have been extensively worked for building stone, both in 

 the river bed and on shore. The rock is very shaly so that it cannot be 

 used for much more thau foundation walls. The openings are indicated 

 by the spots on the map. Large piles have been frequently stored up 

 for market, so that many opportunities for examination were given, both 

 in the stone heaps and in the workings. The evidence that our limestone 

 is sub-carboniferous. Prof. Strong tells me is abundant and satisfactory, 

 both on the organic and stratigraphical sides. Evidence is given by the 

 borings for salt wells, by seeing actual contact with the lower numbers 

 of the carboniferous measures on the east, and contact with the Marshall 

 sandstone — generally regarded as equivalent to the Waverly group^ on the 

 west. Additional evidence is given from the fossil remains, of which 

 Prof. Strong published a preliminary list, as K. S. I. Miscellaneous Col- 

 lections No. 3. He describes Helodus crcnulatus, Cladodus irreyulari.s, 

 scales of Ctcnacanthus, four species of Nautilus three of Allorisma, and 

 several others too imperfect to be determined. IJthostrotion canaden^e, 

 Productus sanciatus, and some specimens of Hemiphronitcs are also relied 

 on for further evidence. Dr. DeCamp has found trilobites which he 

 identified as "Phacops 6?/-/o." He sent them to Prof. A. Winchell for 

 further examination. He has also found tesselated teeth in the Taylor 

 street quarry and bony plates for such teeth. Of corals I have found 

 Cyatliophyllum divaricatum and 0. flcxuosus. Many other corals are found 

 in the drift, but need not be mentioned here. The division of the sub- 

 carboniferous is a more difficult matter. The Lithostrotion, Prof. Win- 

 chell wi'ites indicates the St. Louis group of the Mississippi valley. The 

 strata, are slightly undulating and in one opening there are several 

 layers of the red limestone which will burn to hydraulic lime. 



*50 to 60 ft. to the mile. 



