554 George Barrow — On a Marine Bed in the Yorkshire Oolite. 
It is as follows, in descending Order : 
(«) Four feet of very hard close-grained sandstone, containing fragments of 
soft jet and otlier carbonaeeous matter. 
UA One foot of sandy impure ironstone. 
( c ) Six feet of dark-brown Oolitic ironstone, sligbtly magnetic ; apparently 
unfossiliferous. 
( d ) Two feet of caleareous and ferruginous stone, with a few small fossils. 
(e) Twenty feet of hard, flaggy, micaceous, white sandstone; passing gradually 
downwards into a sandy sbale. 
(/) One foot six inches of sandy marl. 
(ff) F oui' inches of dense limestone, apparently unfossiliferous. 
(/<) Five feet of argillaceous, micaceous shale, much resemblmg the shales of 
the Middle Lias. 
(i) One foot of ironstone, with many specimens of the characteristic Phola- 
domya. 
(c) The position of the above section can best be fixed by the 
presence of a heap of this ironstone (c) lying on the side of the stream. 
Upon an analysis of the ore being made, it was found to coutain 
an average of more than thirty-five per cent. of metallic iron, one 
sample yielding as much as forty-two per cent. of that metal. The 
amount of phosphorus and sulphur was very small, being usually 
less than OT per cent. of each. 
After making a careful survey of this district, I have been 
compelled to arrive at the conclusion that the deposit is of an 
extremely local nature ; there being the clearest evidence that it 
does not continue for more than a hundred yards, either to the 
north, east, or west. Moreover there seems to be a constant tendency 
to the development of an Oolitic ironstone, usually very siliceous, 
in the middle of the bed of sandstone : a feature that can be well 
seen both in the upper part of the Murk Esk, near Julian Park, and 
in Wheeldale. 
The bed does not appear to be continuous in a southerly direction ; 
I rather believe that the ore thins away as rapidly (towards the 
south) as it can be proved to do in every other direction. 
(f) This bed of marl is in places almost composed of what 
appears to be a small Gryplicea, wliich occurs in even greater pro- 
fusion than does Gryplicea cymbium in the Middle Lias. Running 
through the middle of the marl is a thin band of soft jet or, perbaps, 
non-bituminous Coal, with a layer of pyrites above and below. 
When first dug out, the bed has a bright fracture, and is very hard ; 
but on exposure to the air it soon becomes so soft that it can be 
broken to pieces with a very slight blow. 
(i) The lower bed of ironstone does not differ in any essential 
point from its representative near Goathland ; the characteristic 
Pholadomya being equally abundant in both cases. There seems to 
be a greater variety of species in Winter Gill section, but this has 
scarcely been proved up to the present time. 
This lower bed of ironstone, with its characteristic Pholadomya, 
has a very much wider ränge horizontally than might have been 
expected from its small thickness. It can be easily traced along 
the steep banks of the upper part of the Murk Esk, and is seen 
occasionally in the bed and sides of Wheeldale Gill, one of its 
