72 FEANK D. ADAMS ON THE 



In all its characteristics it closely resembles the saudstoues of the " Waverly G-roup," 

 which, in Michigan, overlie the Huron shales. (See report of the Geological survey of 

 Michigan, 1873-76, Yol. Ill, pp. 69-101.) 



The limestone fragments were small and contained no fossils visible to the naked 

 eye, or with the help of a lens. Some of the minute grains mixed in tvith the sand, how- 

 ever, when properly mounted and examined under the microscope, were found to possess 

 an organic structure ; some of them resembling fragments of crinoids, while others had 

 a minutely punctate character and were probably fragments of brachiopod shells. There 

 is nothing, therefore, to indicate the age of the beds from which these limestone frag- 

 ments have been derived. They may have come from the thin beds of limestone inter- 

 stratified with the sandstones of the "Waverly G-roup," or they may be from older strata 

 of Corniferous, or even Niagara age. The very few fragments of quartzite have no dis- 

 tinctive characters by which their origin can be determined ; some of them resemble the 

 quartzite of the more compact beds of the Oriskany formation. 



Peteographical Character of the Sand. 



As will be seen by referring to the table. Nos. VI. and VIII. consist very largely of 

 sand: No.YIII, in fact, is a nearly pure sand, but a portion of it being extremely fine was 

 washed away during the process of elutriation. Another portion of No. VIII was carefully 

 elutriated, and the material of various degrees of coarseness being thus separated, speci- 

 mens of each were mounted in Canada balsam for microscopic examination, while others 

 were prepared in almond oil and in water. The constituents found in this sand are the 

 same as those found in the sands separated from the other samples, although all the 

 minerals here mentioned were not found in every case. A brief description of this sand, 

 therefore, will serve to indicate the character of the whole. 



The coarse portions separated by the washing were found to be composed of the 

 following minerals : — quartz, orthoclase, microcline, plagioclase, hornblende, epidote, 

 tourmaline, garnet, calcite, pyrite, magnetite, spheue (?). 



A few small pieces of the shale and sandstone before mentioned were also present. 



The quartz occurs principally in partially rounded fragments, but also as angular 

 chips, while a number of grains are perfectly rounded with a surface like ground glass. 

 They are generally clear and colourless, but some few have the surface stained red by oxide 

 of iron. Some of them hold the minute black hair-like bodies often seen in the quartz of 

 the crystalline schists. Some of the quartz grains in the sand in No. I. show the peculiar 

 crushed or broken character so often seen in the quartz of gneiss. 



The orthoclase is not nearly so abundant as the quartz and occurs usually in much 

 decomposed grains. It shows a biaxial figure in convergent light. 



Microcline and plagioclase in well characterized grains occur in every slide. Horn- 

 blende occurs in green transparent anisotropic grains, often strongly pleochroic in tints of 

 green. Generally in oblong grains with slightly inclined extinction and absorption £ > CÎ 

 Tourmaline was found in the sands of all degrees of fineness. It occurs in short, stout 

 prisms, terminated at one extremity by a flat pyramid ; the other end is sometimes simi- 

 larly terminated, but is generally irregular. One of the largest of these little prisms was 



