50 LOWER PENINSULA. 



the shore, and extending thence about one mile up the stream. 

 The bluffs consist of nodular, unhomogeneous beds of limestones, 

 interstratified with thin seams of shaly substance of black color. 

 Nearly the entire rock mass is made up of specimens of Stromato- 

 pora mingled with Favosites, Cyathophyllum profundum, Diphy- 

 phyllum archiaci, and other corals, which, by exposure, easily be- 

 come disintegrated. At the foot of the bluffs, blue shales are ex- 

 posed which contain many fossils : Atrypa reticularis, Spirigera 

 concentrica, Spirifer mucronatus, Spirifer zigzag, Spirifer granu- 

 liferous, Rhynchonella, Strophodonta concava, Strophodonta de- 

 missa, Chonetes coronata, Cyathophyllum Houghtoni, Cystiphyllum 

 Americanum, Stromatopora monticulifera, Stromatopora Wortheni, 

 Crinoid stems, and many Bryozoa. 



The lumps of coral and Stromatopora composing the upper 

 beds of the bluffs take a good polish. Deceived by some good- 

 looking polished samples, parties in Detroit were induced to buy 

 the land on which the specimens were found, with the intention 

 of opening a marble quarry. The shattered condition of the rock 

 bluffs, which should have warned them at the first glance, was to- 

 tally ignored, and in the vain hope that, by digging deeper down, 

 a sounder quality of the rock would be found, a shaft was sunk 

 into the shale beds under the bluffs to a depth of 50 feet. It 

 was then that those concerned came to me, asking for advice, 

 which I gave them with sincerity, but a little too late to save their 

 purses. 



Another so-called marble quarry was opened a number of years 

 prior to this experiment, by Mr. Crawford, in the vicinity of 

 Adams Point, in Town. 35, Range 5, east. Sect. 24, which gave no 

 better results. The rock has not the compactness and homo- 

 geneous qualities requisite for marble. The beds in both men- 

 tioned places seem to be identical. A belt of similar limestones, 

 partly covered up by drift deposits, follows the northeastern shore 

 of Grand Lake, connecting the two points. The blue shales below 

 the rock in the one locality are not seen at Crawford's quarry, but 

 there is a probability that the blue shales penetrated in the artesian 

 well at Alpena, 400 feet below the surface, may be the equivalent 

 of them. The next lower beds to this series compose Middle 

 Island, and identical with the Middle Island strata are the out- 

 crops on False Presque Isle, where the ledges project in a low 



