282 Scientific Intelligence. 



4. Note by M. ITOrbigny on the Orbitolina, (mentioned by Mr. 

 Lyell, at p. 186, this volume.) 



Paris, 18th June, 1847. 

 To C. Lvell, Esq. 



Dear Sir, — I have been long acquainted with the fossil body, which 

 you forwarded to me, and at this moment I am printing in an elemen- 

 tary work, all the mistakes concerning it ; it is, in fact, of all genera 

 that perhaps which has been most often misunderstood, and I should 

 call it the greatest culprit in geology. It is a genus nearly allied to 

 Orbitolina, and which I have named, in consequence of this analogy, 

 Orbitoides. It has always been taken for a nummulite, though it differs 

 from it by the most marked characters. I have known many species 

 such as the O. media, papyracea, and that which you have forwarded 

 to me, and which I had designated by the name of Americana. The 

 Orbitoides are found in the cretaceous and tertiary formations, the 

 Nummulina in the tertiary only. Such at least is the result of my 

 numerous investigations on this subject. The species that you have 

 forwarded to me, had been sent me from North America with a great 

 number of tertiary and cretaceous shells; it came to me without any 

 information respecting it, and I am anxious to know where you found it. 



Yours, &c- Alcide D'Orbigsy. 



5. Observations on the Drift Furrows, Grooves, Scratches, and Pol- 

 ished Surfaces of the Rocks of Lake Superior ; by Forrest Shepherd, 

 (in a letter to Prof. Silliman.)— I have noticed, both on the northern and 

 southern shores of Lake Superior, innumerable longitudinal furrows, 

 grooves, scratches and also smoothly polished surfaces, upon granite, 

 sienite and greenstone. These grooves run generally in a direction 

 north and south, varying occasionally with slight obliquity. When the 

 surface of the lake is quiet, these marks may be seen at a considerable 

 depth beneath the transparent water corresponding with those seen on 

 the same rocks at the present level of the lake. You may thence as- 

 cend upwards on the banks and hills, on the islands and shores of the 

 lake, and by removing the moss and vegetation, you will find these 

 marks continue with remarkable uniformity until you reach the sum- 

 mits of the Huron Mountains, which according to the measurement o 

 Capt. Bayfield, are situated eight hundred feet above the present level 

 of the lake. While standing on the summit of these mountains, jn 

 some places I found the compact undecomposed feldspar, as smoothly 

 polished as if it had been soft wood recently subjected to the carpenters 

 plane or drawing knife ; while in other places were to be seen marks 

 and furrows as above mentioned. These appearances, which I have 

 described, are all upon rocks in place, and could not, I think, have re- 

 sulted from natural structure. Nor could they have resulted from 

 causes now in operation on the shores of this great body of ires 

 water ; for there is no perceptible difference between the marks on t 

 same kind of rock at the present level of the lake, and those at a grea 

 height or lower depth. By enumerating the concentric circles of 

 largest trees (Pinus abies) which are now standing on the shores of 

 lake, only three or four feet above the surf, and comparing them w 

 the decayed trunks of similar ones whose stumps have been ? rese f T \\ v 

 by having been charred by the fire passing, over them, it is P er,eC : 



