THE LIAS MAULSTONE OF LEICESTERSHIRE. 
66 
(b.) Greenish arenaceous rock, locally a “jack” 
in upper portion, Belemnites, Terebratula 
punctata, and Rliynchonella tetraedra. The 
lower portion of this bed is nodular and 
veined with calcite ... ... ... ... 4 6 
(a.) Greenish arenaceous rock, with “jack” in 
upper half; the lowest six inches contain 
many phosphatic nodules, Gresslya lunulata, 
G. intermedia, Pleuromya sp. Rliynchonella 
tetraedra, and Terebratula punctata... ... 8 6 
* 18 ^5 
Middle Lias: Shales —with bands of sandstone and 
scattered limestone nodules ... (exposed) 13 0 
The dip is here very well shewn. It is about 1° in a 
S.E. direction. 
Note. —The Marlstone Rock is traversed by numerous joints. Along 
these fissures as also along the bedding planes the iron carbonate has, 
to the depth of a few inches on either side, become converted into 
the hydrated oxide, causing the stone to assume a yellowish brown 
colour. 
The uppermost stratum, or rather the top layer of this 
stratum is remarkable for the organic remains it contains. 
Of these, one of the Ammonites, A. acutus, is especially 
noticeable, for it occurs in great numbers and in all stages of 
growth, yet not a single individual has ever been found else¬ 
where in the district. In addition, we find several other 
Ammonites and some interesting little Gastropoda, as well as 
ordinary bivalves and Bracliiopoda. This top bed, or at any 
rate the special fauna it contains, is extremely local, being, so 
far as I know, limited to Tilton. On the north side of Robin- 
a-Tiptoes there is a brickyard section which exposes the 
upper beds of the Marlstone Rock and its junction with the 
Upper Lias shales; but although this point is only half-a- 
mile from the Tilton section we see no trace of the A. acutus 
bed.* 
* A somewhat similar fossiliferous bed, containing some Upper 
Lias forms, has been noticed at the top of the Marlstone of Oxfordshire 
by Mr. Beesley, of Banbury, and is considered by him to be a passage 
bed to the Upper Lias. The A. acutus band at Tilton, however, 
although it contains certain Upper Lias forms, cannot properly be 
considered a passage bed. 
('To be continued.) 
