213 Miscellanies. 



will be remembered that Mr. Logan (Proceedings Geol. Soc. London) 

 found animal tracks on the coal measures of Nova Scotia, (see this Jour- 

 nal, Vol. XLV, p. 308,) which was the first intimation we had of the proba- 

 ble existence of air-breathing animals at any period earlier than the new 

 red sandstone. We have, however, never seen any figures or descrip- 

 tions of the tracks found by Mr. Logan, nor are they yet published so far 

 as we know. Dr. King's discovery is of great interest, from the novel 

 forms which he represents in the drawings accompanying his papers. 

 Only two of them can probably be referred to a biped animal; these 

 are ornithoid tracks, similar to (but not identical with) some of those 

 figured by Prof Hitchcock. 



The other five figures are referable to quadrupeds, of which there are 

 at least four different species, if not genera. His figures (No. 6) are dis- 

 tinctly referable to an animal having the same inequality of step as the 

 Cheirotherium, and other Batrachians. The figures 3, 4, 5, and 7, are 

 probably quadrupedal, but differ entirely from any thing else of the sort 

 we have seen ; there is a large circular imprint, surrounded by five toes ; 

 in one case circular, in another long and ovate, in a third they are of 

 an intermediate character. The tracks found by Mr. Logan in Nova 

 Scotia were referred by Mr. Owen to the order of Eeptilia ; some of 

 these may be allied, but others are too anomalous for even a conjecture 

 with regard to their relations. Provisional names are proposed by the 

 author for the tracks. But we will not anticipate the interest of Dr. 

 King's paper, which will be published in our next. 



3. Formula of the Masonite of Dr. Jackson.* — This mineral in its 

 composition agrees with no other. If we allow for a slight deficiency 

 in silicic acid, and suppose the manganese and magnesia to be acci- 

 dentally present, it evidently consists of simple silicates, and is com- 

 posed of 2 atoms silicate of alumina -j- 1 atom silicate of protoxide 

 of iron -|- 1 atom water, as thus shown : 



Atoms. Ratio. 



Silica, 33-20 16-60 3"! 



Alumina, 29-00 12-88 2 \ Formula: 



Protoxide of iron, 25-93 5-76 1 j 2AlSi-fFSi + Aq.t 



Water, 5-60 5-00 1 j 



The specimen analyzed was a portion of a pure crystallized mass, 



which contained no sensible mechanical mixture, whereby the analytical 



results could lead to false conclusions as to the specific nature of the 



— • 1 



* This notice of the Masonite, — containing additional particulars to those which 

 were given of that mineral in Mr. Alger's edition of Phillips's Mineralogy, p. 132, — 

 was furnished for our last No. but was necessarily postponed. — Eds. Am. Jour. 



f The formula of this mineral in chemical symbols is 2^1 Si + Fe3 Si + SH. 

 — Ecs. 



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