I 1 6 LO WER PEN INS ULA . 



Carbonate of lime 94 per cent. 



" magnesia i " 



Iron I " 



Quartz sand 4 " 



The entire section comprises about 18 feet of strata. North of 

 Jackson, on Portage River, about a mile east of its entry into Grand 

 River, the carboniferous limestone is found on top of a hill, the 

 southern slope of which is formed by steeply inclined sand rock and 

 shale beds, with seams of coal. Their dip is southward. 



The lowest beds of limestone exposed are of a nodular, brecciated 

 character, composed of rounded lumps of a light-colored, smooth 

 fracturing limestone, with seams of green-colored harder and softer 

 shaly substance filling the interstices ; the higher beds are a 

 smooth, compact, brittle lime rock of light color, also in shatter- 

 ed condition, and full of stylolithic segregations. Fossils are rare ; 

 sometimes a Productus, Allorisma clavata, Bellerophon sublaevis, 

 or a species of Rhynchonella, is inclosed. The strata seen in the 

 quarries reach a thickness of 15 feet. Mr. Wright, the owner of 

 one of the quarries, drilled a hole within its limits to a depth of 53 

 feet. First, 9 feet of the upper lime rock in the quarries were 

 penetrated, then 5 or 6 feet of the greenish, brecciated lime rock, 

 followed by 2 or 3 feet of a reddish-colored limestone. Below 

 came 8 or 10 feet of hard, calcareous sand rock, and, lowest, a 

 coarse, soft sandstone. Only about 30 steps from, this bore-hole, 

 across the road, a shaft of 25 feet in depth was dug, which first 

 went through highly inclined black shales, and then through sand 

 rock belonging to the coal measures. 



On the opposite, south side of Portage River, the sloping hill- 

 side over which the road to Jackson leads is formed by coarse- 

 grained, soft sandstone similar to the sandstone of the Jackson coal 

 mines. Near the top, greenish calcareous sand rock, with seams 

 of greenish shale, is seen in the ro1.d ditches, and right above 

 it are 5 feet of well-stratified limestones with delicate laminar 

 striation resembling a Stromatopora, but apparently not of or- 

 ganic origin. The same limestone beds are pervaded by nu- 

 merous vertical flexuose channels, laterally anastomosing, and 

 much resembling moulds formed around the clustered stems of a 

 Syringopora. Some of the cavities were filled with spar, but I 



