1 IS KEY. J. E. CROSS ON THE GEOLOGT OF KW. LINCOLNSHIRE. 



Along with these two Ammonites, apparently from the lowest 

 beds upwards, there are various Ostrece and Gryphcece in greater 

 numbers than one might have expected : — one kind approaching to 

 the GrypTicea incurva of the higher beds, yet keeping, I think, a 

 distinctive form ; another, large and wide, which I have been 

 accustomed to call G. grandis, but I dare say it is not really new. 

 There is also the Ostrea irregularis or liassica and the 0. rugata of 

 Quenstedt. I give a list of the fossils found in this and the other 

 beds of the district. 



Above this the true Gryphcsa-incurva zone is well developed and 

 well exhibited in a deep railway-cutting (that of Frodingham) 

 which strikes the hill just about the top of the A.-angulatus zone. 

 It consists of a series of blue clays and rocks in layers (figs. 2 & 3, i), 

 and contains Ammonites of the BucMandi type. The figure of A. 

 BucTclandi, engraved in Dr. Wright's ' Ammonites of the Lias/ is 

 there stated to have been from a specimen found in a Lias railway- 

 cutting near Brigg. This is doubtless the spot I am treating of. 

 Ammonites semicostatus is prettj r common, GrypTicea incurva in thou- 

 sands, and most of the usual fossils of the zone, Lima gigantea, 

 Pentacrinus of two kinds ; >Spirife?*ina Walcotti is rare. 



It is next above these beds that we come upon the peculiar and 

 interesting formation of our Lias, viz. a thick and rich deposit of 

 iron-ore (figs. 2 & 3, Ti). Fifteen years ago this formation was wholly 

 unknown ; and it is entirely due to the persevering investigations of 

 the present proprietor, Mr. R. Winn, M.P., that it has been brought 

 to light. 



And first, as to the geological place of this ore. It is un- 

 doubtedly Lower Lias, and low down in the same. The Ammo- 

 nites it contains are still chiefly the keeled Arietes, or those keeled 

 Ammonites which are next above them — A. BucTclandi or some 

 cognate species, A. semicostatus (commonest of all, but very badly 

 preserved), A. Conyheari, A. Brookii of Quenstedt's Jura (which 

 seems not to be Sowerby's A. stellaris), the species called A. aureus 

 by Dumortier, one solitary specimen which is undoubtedly the 

 A. Boucaultianus of D'Orbigny, A. Boblayi of Buckman, and two 

 large species which may, perhaps, be identified with figures in 

 Quenstedt's Jura, under the names of A. Scipionanus and corn- 



Univalves are very rare (as indeed they are throughout the whole 

 district) ; but Pleurotomaria anglica has been found. Lima gigantea 

 is large and common ; there is also a dwarf gigantea, if I may so term 

 it, and Lima Hermanni or antiquata ; GrypTicea, usually a little wider 

 than the ordinary incurva, but passing insensibly into it ; Nautilus 

 striatus, Belemnites acutus. Besides these ordinary shells there are 

 a few which are somewhat out of the common line : — a small Myo- 

 concha, apparently the M. Oxynoti of Quenstedt ; the Gervillia be- 

 tacalcis of the same author ; and, I think, his Cucullcea ovum. A 

 pretty little Astarte is very common, which Mr. Etheridge identifies 

 with his A. dentilabrum. There is also, in considerable plenty, a 

 small Hippopodium, greatly resembling one which Mr. C. Moore has 



