STATE GEOLOGIST. 127 



striped and mottled with red, or even of a uniformly brick red 

 color. It varies equally- in hardness, being sometimes suffi- 

 ciently solid for grindstones and building stones. The State 

 Prison is built of a rock supposed to be this. The material for 

 the county offices at Ionia was also derived from the same 

 source. 



This rock embraces numerous comminuted remains of vegeta- 

 tion, and some well preserved stems of Catamites and Lepido- 

 dendron. 



Although I have treated separately of the Parma Sandstone, 

 the Coal Measures, and the Woodvillo Sandstone, there is no 

 doubt that they all belong strictly to one geological epoch, and 

 constitute what, in a more extended sense, may be designated 

 the coal measures. This remark, however, is somewhat more 

 applicable to the Woodville than the Parma Sandstone. 



18.— Superficial Materials. 



No traces have yet been discovered in the Lower Peninsula, 

 of any of the geological formations intervening between the 

 Ooal Measures . and the Boulder Drift. Drift materials are 

 strewn over nearly the entire surface, and constitute a very 

 serious obstacle in the way of the investigation of our geology. 

 A large number of facts and observations is on hand as data 

 for the discussion of this formation, but it will be necessary to 

 content ourselves with a few general remarks, 



Numerous evidences exist of the movement of heavy bodies 

 over the underlying rocks, previously 'to their burial by the 

 Drift. Wherever considerable surfaces are found exposed, they 

 are seen smoothed and striated in the manner usually attributed 

 to drift agency. The most remarkable- examples are seen upon 

 the Helderberg limestone at Brest, Stony Pi, and Pt. aux Peaux 

 At Stony Pt., the surface of the limestone has been denuded 

 of soil by the action of the waves, over an area of several acres. 

 The whole surface is level, smooth and floor-like, and covered 

 with a set of striae running in perfectly parallel lines N. e0° W. 

 One deep groove is seen belonging to this set The most 



