340 On the Parallelism of Coal-Seams. 



approaching to it. The only point in which L. gemmea, as described 

 by Prof. Frey, seems to resemble it is the white tips to the antennae. 

 In no other respect does his description apply to P. robiniella. 

 What then is L. gemmea, Frey ? It seems to me that Prof. Frey, is 

 mistaken in supposing that it was bred from locust leaves. Such a 

 mistake might well be made in such a confused jumble of leaves as 

 Prof. Frey had, and as it is certainly neither P. robiniella nor L. 

 robiniella, it must, if bred from the locust, be either a variety of L. 

 ornatella, or a new species. The description scarcely admits the first 

 of these alternatives. But if it is a new species, I do not think it can 

 be a leaf miner of the locust, in view of the close study and observation 

 which the locust miners have received in this country. The confusion 

 of Prof. Frey's different kinds of leaves, and the fact that he only 

 mentions the three mines in locust leaves, which were already known 

 to belong to L. robiniella, L. ornatella, and P. robiniella. I think, 

 then, that L. gemmea is not a locust leaf miner, and for the present it 

 is impossible to say whether or not it has been previously described. 

 Very certainly it is not P. robiniella, Clem., nor anything like it. At 

 present it is utterly unknown and unknowable to everyone, save Prof. 

 Frey. 



In addition to what has been formerly said, as to whether P. rob- 

 iniella, Clem., is or is not properly a Gracilaria, I will add, that the po- 

 sition of the legs in the living specimens is the same as in Gracilaria, 

 though the anterior portion of the body is scarcely so much elevated 

 as in larger species of Gracilaria, and the pattern of coloration closely 

 resembles that of G. salicifoliella, Cham., and less closely G. hollairella, 

 Zell. 



On the Parallelism of Coal-Seams. — By E. B. Andrews. [From the 

 American Journal of Science and Arts, July, 1874.] 



In the April number of this Journal [republished in the July num- 

 ber of this Journal, page 267], Dr. Newberry calls in question my 

 views of the general parallelism of coal-seams, derived from the study 

 of our Ohio coal-measures, and thinks them not only "untrue" but 

 "calculated to do positive and pratical harm." The only point of dif- 

 ference between us, of any interest to science, is, whether the ancient 

 shore lines, Avith their coal-marshes, subsided in an even and uniform 

 way, or very unevenly, so as to bring each marsh to greatly varying 



