Postscript. 316 
posits. From this disposition of the beds, it happens that a deep cut in 
one place may pass exclusively through the limestone, and then at an- 
other, in the immediate neighborhood, through the incumbent newer 
strata. At Claiborne itself the bluff at the new landing consists of the 
calcareous formation about 150 feet thick, with a capping of 20 feet 
of the newer deposit, while about a mile lower down in the same bluff 
the appearances are reversed, and the upper formation occupies more 
than 100 feet of the higher part of the bluff, the calcareous beds crop- 
ping out from beneath. The section given by me in the Quarterly 
irnal of the Goological Society, No. 4, p. 488, in reference to the 
PS - Jacksonboro’ beds in Georgia, will enable you to understand this ar- 
__- Tangement.” 
2. Discoveries with the Great Refractor at Cincinnati.—In an inter- 
esting communication published in the Daily Atlas (Cincinnati) of Feb. 
1]th, 1846, Prof. Mitchell, the able director of the Cincinnati Observa- 
tory, announces that he has devoted all the time he could command, to an 
examination, with the noble instrument pertaining to that establishment, 
of a zone in the heavens, extending from 15° to 40° of Southern Decli- 
nation. The number of new double and multiple stars already thus 
discovered amounts to one hundred and fifty five. Of those of the 
former class, the most interesting is Antares, a star of the first magni- 
tude in Scorpio, which on the 13th June, 1845, Prof. M. detected to be 
accompanied by a minute stellar companion, distant only 17”, and this 
discovery he has confirmed by repeated observation. There is every 
reason to suppose that this splendid and often observed star, had never 
before been seen double. Of the latter class, is a triple star in the 
Pleiades. When first discovered, several months since, the three stars 
were precisely in the same straight line. By an observation of Feb. 9, 
1846, it appeared that “the line drawn through the two minute stars, 
no longer passed through the centre of the larger star, and shows 
clusively a rapid motion in the minute star next to the principal one.’ 
We shall wait with much interest for the many important discoveries 
yet to be revealed by the aid of this powerful instrument. 
The plates designed to accompany Mr. Conrad’s article on Eocene — 
Fossils, at page 206 of this number, did not arrive from Philadelphia in 
season to be inserted in their proper place. They will be issued in our 
next, 
