304 STATE POMOI.OUICAL SOCIETY. 



the drift came, are as follows: First, the Helderberg group, composed of a 

 clayey carbonate of lime, abounding in fossil remains. Next is the Onondaga 

 salt grouj), a narrow out-cro}i on tlie north shore of lake Michigan, near the 

 straits, and underlying the bed of the lake, containing plaster and water-lime 

 beds. Next is the Niagara group, a narrow out-crop, composed of crystalline 

 magnesian carbonate of lime. 



Next is the Hudson River group (I omit the Clinton group, which is not 

 known to out-croji in that direction), composed of clayey shales underlaid by 

 blue limestone. Next is the Trenton group, also a limestone formation. Next 

 Calciferous and Jiake Superior sandstone, highly impregnated with the peroxid 

 of iron and manganese. Next is the Azoic formation, a name given to the 

 lower stratified rocks, which contain no fossil remains. Tiiese rocks are com- 

 posed mostly of lime, alumina, silica, and iron. Next the granite, composed 

 mostly of cpiartz, felsi)ar and mica; and, lastly, the Trap rocks, composed of 

 potash, alumina, silica, lime, magnesia, manganese and iron. All of these 

 rocks have contributed their ([uota to the general mass of drift that covers this 

 region. The great eruptions whiclt tlirew uj) the granite liills of the upper 

 peninsula and formed the basin of Lake Superior, also depressed the whole 

 interior of the lower peninsula, forming a great geological basin, — thus giving 

 the whole rock strata composed of tlie above formations a southward di[) from 

 Lake Superior to the center of the basin, leaving the upturned edges of the 

 different formations overlapping each other like the shingles of an inverted 

 house roof. These upturned edges were broken, worn, and furrowed liy the 

 great ice-flows of Llie glacial })criod, tliat came down from the north-northwest, 

 scooping out the bed of Lake jMichigan from the softer rocks, and mixing and 

 pulverizing the debris and detritus of the different formations, in its southward 

 course, into one conglomerate mass, spread it over tlie land, and deposited it in 

 the morains whose peaks and ridges are conspicuous landmarks from the valley 

 of the Muskegon to tlie mouth of Grand Traverse Bay. As proof of this ori- 

 gin, we find blocks of granite of all sizes, from that of several tons to the peb- 

 bles on the beach, scattered over the country ; also blocks of trap in the same 

 manner, and lime stones and lime gravel, wliicli correspond exactly witli the 

 foregoing lime formations in structure, material, and organic remains. Frag- 

 ments of the various limestone formations are found in tlie greatest abundance 

 in every variety of soil, at all elevations, and in every variety of form, — in mas- 

 sive blocks, angular fragments, broken slabs, rounded nodules, worn gravel, 

 tiny scales, and sand-like grains. The fossil remains of the Helderberg group 

 are scattered in the greatest profusion all over the country, and can be gathered 

 with little search from every cultivated field. 



The soil being derived from this source, contains all the earthy matters that 

 the highest fertility requires, and that in lasting abundance. Being composed 

 of such a variety of materials, in such a varied state of pulverization, it is very 

 porous, and susceptible to atmos[)hcric influence to a great depth and to a high 

 degree. The air, mingling freely with the porous soil, slowly acts upon this 

 great store-house of alkaline material and renders it soluble in water and ready 

 to be used in Ijuilding up the organic structures of plants. 



It is this abundant supply of soluble alkaline matter that covers our uplands 

 with such an immense growth of maple, ash, and elm timber, the very species 

 that require the greatest sui)ply of that material. So great is the supply of 

 calcareous matter, that in boiling down the sap of the maple, in the manufac- 

 ture of sugar, a large amount of malate of lime is always deposited at the bot- 



