APPLICATION TO THE SYLVAXIA SANDSTONE 655 



time^ thereby reaching its present remarkable condition of piirit}'" (page 

 246). Derived from such a parent bed and inheriting such character- 

 istics^ the perfection of the aeolian granule as typified b}^ the Sylvania is 

 not so surprising^ in comparison with which the Sahara sand is in but a 

 state of infancy. (Compare figures 3 and 4, plate 45; figures 1 and 2, 

 plate 4:6, and those on plate 47). 



In order to ascertain whether any evidence might be found in a study 

 of the inclusions contained in the Sylvania and Saint Peter granules 

 calculated to disprove, or render improbable the origin of the former 

 from the latter, a half dozen samples of each formation were submitted 

 to Prof. C. H. Smyth, Jr., of Princeton University; to Prof. C. P. Ber- 

 key, of Columbia University, and to Dr. A. C. Lane, of Tufts College, 

 for microscopic study. Through their kindness we are able to append 

 the following statements : 



"I can find uotliiiig in the way of inclusions that is distinctive, but merely 

 the ordinary minerals and fluids of granitic and vein quartz. So far as I can 

 see, there, is nothing to show that the Sylvania is derived from the Saint Peter, 

 while, on the other hand, there is no indication that it is not so derived. Thus, 

 if you have other lines of evidence indicating such derivation, the inclusions 

 in the quartz grains do not, so far as I can see, give any conflicting testimony. 



"C. H. Smyth, Jr. 



"Peijs'ceton, New Jersey, Jiuie 10, 1910." 



"Before leaving home I mounted some of each sample of sand and looked 

 them over with such care as I could. I must say that I can not see any differ- 

 ence in the two great sources in anything that could be regarded as an essential 

 character. Both show the same types of sources — the quartz-bearing crystal- 

 line rocks — and both show fine sorting and rounding; also both are much in- 

 clined to show enlargement by addition of secondary quartz. I have not been 

 able to undertake more elaborate comparisons. It seems to me to be almost 

 a hopeless task to prove very much in this direction for these reason;^." Both 

 formations' ultimate supply of materials must be traced back to the crystal- 

 lines — the same or similar in origin, character, occurrence, distribution, and 

 composition. If two grains side by side in the Sylvania were immediately de- 

 rived — one from the Saint Peter and one from the crystallines direct — I don't 

 see any very good way of proving which was which. If one were more round, 

 it might be assumed to be the Saint Peter one, but even that I am somewhat 



■^ It was not the thought of the writer that the origin of the Sylvania from the Saint 

 Peter could he demonstrated from a microscopic examination of the grains of each for- 

 mation, since, as pointed out hy each of these investigators, they might have had a 

 common but independent origin and similar history. With the field evidence, however, 

 pointing to such origin, the writer was desirous of learning whether the granules them- 

 selves furnished any evidence that would render such an hypothesis untenable. From 

 the three reports given, the reader will note that no such contradictory evidence has 

 been found, and such an origin for the Sylvania becomes possible. The probability of 

 such an origin is an entirely different matter. 



