,S^(V CJiarles Lyell. 355 



specimens vary but little in relative proportions, though they differ 

 considerably in size. The specimen figured is from one of the numer- 

 ous impressions, in the slabs, that make the sidewalk, on Tcrrence Koad 

 near Forest Avenue. ^ It is 4 inches in length ; length of cylinder 2§ 

 inches ; diameter of ball cavities | inch ; diameter of cyHuder \ inch. 



Fig. 26. Ai-thraria. hiclavata. 

 [Etym 6icto!u<a— double clubbed] 



The form is constant and prevails, in the rocks, from 300 to 400 feet 

 above low water mark, at Cincinnati, and in the same range in distant 

 quarries. It may have a greater vertical range, though I have never 

 observed it, in either the lower or higher rocks of our Group. As it is 

 found on slabs, exclusively, it does not make a good cabinet specimen 

 and therefore but few have ever been collected. 



Sir Charles Lyell. 



[From the American Journal of Science and Arts, October, 1875:] 



No European geologist was so well known, personally, in the United 

 States as Lyell. His two visits to this country, in 1841 and 1845, re- 

 corded in four volumes of travel characterized, by great good judg- 

 ment, large mindedness and catholocity, made his name familiar 

 throughout the land, and gave a degree of popularity here to his philo- 

 sophical and technical writings which they would otherwise have hard- 

 ly obtained. 



Called by Mr. Lowell to Boston in 1841 to deliver a course of twelve 

 lectures on Geology before the "Lowell Institute," Lyell was the first 

 European, of eminence in science, ^vho appeared upon the platform as 

 a lecturer before an American audience. That his lectures were high- 

 ly esteemed is well known, and it was a sufficient evidence of this that 

 he was again invited to Boston on a like commission in 1845-6, and 

 before the same institution. The personal relations and friendships 

 commenced on these occasions endured to the end, and were rendered 



