240 
FERRUGINOUS SANDS AND GRIT WITH PLANTS. 
by a mass about 12 to 15 feet thick of reddish-coloured detritus. The upper stone 
beds are rusty-yellow, slightly coherent, sandy grits, with occasional flattened geodes 
of black and brown oxide of iron. In these respects, indeed, they are not very dif- 
ferent from the upper ferruginous beds under the Sparrow Hills, a continuation 
of the same plateau. The whiter grit extracted for building and millstone occurs 
in subconcretionary masses or flattened ellipsoids from two to four feet thick, and 
forms the lower part. If prolonged across the Moskwa, these horizontal beds would 
be directly superposed on the Jurassic strata of Koroshovo, and we thus learn, that 
the detached blocks of grit in the loose overlying sands of that village, are simply 
the harder beds in situ which have resisted denudation. 
For a long time the only fossil we had obtained from these sandstones was a 
cast of a shell evidently marine, and apparently belonging to the genus Lucina. The 
plants above mentioned have therefore proved to be a most important addition. 
Two of the best-preserved specimens of these plants were discovered in the 
ferruginous sandstone of Tatarova. On sending the drawings of them to Dr. 
Goppert of Breslau, that eminent botanist has referred two of these specimens to the 
genus Pterophyllum of the family Cycadese, and his description of the best-pre- 
served species, which he has named Pterophyllum Murcliisonianum, will be given in 
Part III. of this work. Other closely allied plants, belonging either to the same 
genus or to Calamites, with traces of Coniferse, have been found by Mr. Auerbach 1 
in a white siliceous grit near Klin, which, from the lie of the country and nature of 
the rock, Mr. Frears has no doubt is of the same age as that of Tatarova. These 
will also be described in the sequel. Again at Troitskoi on the Moskwa, three 
versts above Tatarova, Mr. Frears has found similar sands to be associated with 
a deposit of calcareous shale and marl, also highly ferruginous and full of equiseta- 
ceous plants. As no drawings of these last-mentioned remains have yet been sent 
to us, we are unable to reason upon them, except by general analogy ; whilst it 
is very interesting to find, that they are there associated with fishes’ teeth and 
a quantity of scales of fishes, which, when adequately examined, will no doubt 
enable geologists to place these beds still more precisely in their geological position 2 . 
1 One of these plants has been named by M. Auerbach Scolopendrites pectinatus. 
2 In respect to Jurassic fishes, it is important to state, that a fish-palate found on the banks of the Volga 
having been sent to Dr. Mantell, he is about to publish it in his new work, * The Medals of Creation,’ 
under the name of Gyrodus Murchisoni j expressing also his opinion, and that of Agassiz, that it is an 
oolitic form. 
