496 



NA TURE 



\Scpt. 2 2, I 88 I 



Buchiauus and M. Nodotianus. It stands on the extreme limit 

 of tlie t;eiius, connecting it with Pentacrinus on ihe one hand, 

 and with the free Comatulida on the other. It is thus a synthetic 

 type, as would naturally be expected from its geological position ; 

 for it is probably the earliest known species of the genus, except 

 perhaps for two doubtful Liassic forms, which are known only 

 by isolated plates and stem-joints. 



Oliservations on the two Types of Cambrian Beds of the BHtish 

 Isles (the Caledonian and liil>erno-Cainbrian)^and the Conditions 

 under which they loere respectively Deposited, by Prof. Edwai'd 

 Hull, LL.D., F. U.S. — In this paper the author pointed out the 

 distinctions in mineral character between the Cambrian beds of 

 die North-West Highlands of Scotland, and their assumed 

 representative in the east of Ireland and North Wales. In the 

 former case, which included the beds belonging to the " Cale- 

 donian type," the formation consists of red or purple sandstones 

 and conglomerates ; in the latier, which included the beds be- 

 longing to the " Hiberno- Cambrian type," the formation consists 

 of hard green and purple grits and slates, contrasting strongly 

 \\ ith the former in sti'ucture and appearance. These difference-, 

 the author considered, ^^•ere due to deposition in distinct basins, 

 lying on either side of an archrean ridge of crystalline rocks, 

 which ranged probably from Scandinavia through the central 

 Highlands of Scotland, and included the north and west of 

 Ireland, with the counties of Donegal, Derry, Mayo, Sligo, and 

 Galway, in all of which the Cambrian beds were absent, so that 

 the Lower Silurian repose directly and uncomformably on the 

 crystalline rocks of Laurentian age. As additional evidence of 

 the existence of this old ridge, the author showed that when the 

 Lower Silurian beds were in course of formation the arch^an 

 floor along the we^t of Scotland must have sloped upwards 

 towards the east, but he agreed with Prof. Ramsay that the 

 crystalline rocks of the Outer Hebrides formed the western limit 

 of the Cambrian area of deposition, and that the basin was in 

 the form of an inland lake. On the other hand, looking at the 

 f^ossil evidence both of the Irish and WeLh Cambrian beds, he 

 was of opinion that the beds of this basin were in the main, if 

 not altogether, of marine origin, and that the basin itself had a 

 greatly h ider range eastward and southward, the old archajan 

 ridge of the British I.-les forming but a small portion of the 

 original margin. 



On a Discovery of Fossil Fishes iti the NiW Ked Sandstone of Not- 

 tingham, by E. Wilson, F.G.S. — The author called the attention 

 of the Section to a recent discoveiy of fossil fishes in the Lower 

 Keuper Sandstone of England — a circumstance of sufficient rarity 

 in it-elf, apart from any paljeontological results, to deserve at 

 least a passing notice. During the construction of the Leen 

 Valley Outfall Sewer in 1S78, a remarkably interesting section 

 was given by the tunnelling driven through Rough Hill, or Col- 

 wick Wood, near Nottingham, showing the lower beds of the 

 waterstones resting on a denuded surface cf the " Basement 

 Beds " of the Keuper. The lowe-t stratum of the waterstone 

 was a sandstone about a foot thick, with streaks of red and green 

 marl, and a seam of pebbles at the ba^e. The fishes occurred in 

 this bed, and chiefly in a thin seam of red marl overlying the 

 pebbly seam at the very bottom of the Waterstones ; they were 

 present in large numbers, as if in a shoal, for a distance, in the 

 line of section, of about thirty-three feet. The specimens ob- 

 tained have been examined by several competent authorities, but 

 unfortunately their state of pre-ervation is so bad that nothing 

 certain can be made out as to their precise zoological affinities. 

 Dr. Traquair, however, believes that they probably belong to 

 some species, new or old, of the genus Semionotus. 



Glacial Sections at York, and their Relation to the later 

 Deposits, by J. Edmund Clark, B.A., B.Sc, F.G.S. —The 

 York area chiefly consists of glacial beds, which form-the high 

 ground and various extensive low tracts more or less remote 

 from the Ou^e. Glacial depressions have been filled up with 

 brick-earths, and, in exceptional cases, peat- beds. Where the 

 river channel is narrowed below the city, the crests of the banks 

 are capped with gravels. The peat-beds of Campleshon Fond 

 and part of St, Paul's Square rest on the levels covered with 

 brick-earth. Near Ouse Bridge a peat-bed 50 feet down, at 

 Bratt's Brewery, has been called interglacial ; 1 ut the beds 

 above it cannot positively be asserted to be glacial ; for at the 

 waterworks similar beds appear, in which plant-roots were de- 

 tected 20 feet down. The following sequence of the beds can 

 be established : — 



Brick earths. — At the Harrogate Signals, a quarter of a mile 

 further north, the junction of the upper beds with glacial (or 



probably glacial) beds is seen. At a few points bosses of 

 boulder clay protrude even here through the upper beds, whilst 

 elsewhere depressions are filled with brick-clays, now extensively 

 worked. 



Gravels. — The gravel beds at Fulford and on the opposite 

 side of the Ouse are much alike. The beds are irregular, 

 roughly stratified, with boulders of a quarter-ton weight. 'Ihe 

 stones are precisely the same as those in the boulder clay ; some 

 limestone boulders are still striated. At the gravel pits now 

 being worked on the Bishopthorpe Road a metatarsal of Ursus 

 spelceus (or U. arctos) was found this spring. There seems to 

 be no previous record of any carnivorous remains from this 

 neighbourhood. 



Glacial Sections. — The deepest glacial sections were some made 

 in drainage-work at the Friends' Retreat, in 1876, a drift, 650 

 feet long, cutting through the hill from north-west by west to 

 south-east by east. At the highest point this was 47 feet below 

 the surface. Shafts were sunk evei7 50 feet. Nothing but 

 glacial beds were met, tough boulder clays, gravelly beds, and 

 sand beds. The latter were variously inclined and much cut 

 up, rarely continuing any great distance. Indeed everything 

 pointed to the whole mass being made up of independent parts, 

 heaped and piled against each other. The largest boulder 

 brought up weighed about 600 pounds, which is as mucli as any 

 seen near York in situ, except, possibly, one still to be seen on 

 the iVIount. Some of those in the museum grounds must weigh 

 more. Among other stones two lumps of coal were brought up. 

 The most extensive series of sections are those on the site of the 

 New Goods Sta'ion. For this a level was obtained four acres 

 or so in extent, and 3 to 12 feet below the old surface. Un- 

 fortunately there are no records of the sections made in this part. 

 The stones found, though including many from the Lake Dis- 

 trict, chiefly come from the Carboniferous beds of the West 

 Riding. Limestones are usually scratched and often beautifully 

 polished. At all the places mentioned occasional specimens 

 occur from Lias a' d Oolite beds, so that an easterly drift must 

 have sometimes counteracted the prevailing set from the west. 

 These glacial beds approach nearest to the purple boulder clay 

 of Messrs. Searles V. Wood and Harmer. Floating ice, how- 

 ever, rather than the moraine profondc of an ice sheet, seems 

 best to account for the mixture of tough boulder-clays with beds 

 of boulders, gravel', and current-bedded sands. The post- 

 glacial deposits are worked to depths of 30 feet and more ; in 

 the river-bed they may exceed 50 feet. The river is now 60 or 

 70 feet above its ijreglacial bed, and probably 40 or 50 above 

 the level to which it first cut down in the opening of the post- 

 glacial epoch. 



The Devono-Silurian Formation, by Prof. E. Hull, LL.D., 

 F.R.S., &c. — The beds which the author propised to group 

 under the above designation are found at various parts c.f the 

 British Isles, and to a slight extent on the Continent. The for- 

 mation is, however, eminently British, and occurs under various 

 local names, of which the following are the principal : — 



England and Wales 



Divonshire. — "The Foreland Grits and Slates," lying below 

 the LoM-er Devonian beds (" Lynton Beds "). 



IFelsh Borders. — "The passage beds " of Murchison, above 

 the Upper Ludlow Bone bed, and including the Downton Sand- 

 stone, and rocks of the Ridge of the Trichrug. These beds form 

 the connecting link between the I^stuarine Devonian beds of 

 Hereford (generally, but erroneously, called the "Old Red 

 Sandstone ") and the Upper Silurian Series. 



South-East of England (Sub-Cretaceous district).— The author 

 assumed, from the borings at Ware, Turnford, and Tottenham 

 Court Road, de'cribed by Mr. Etheridge, that the Devono- 

 Silurian beds lie concealed between Turnford and Tottenham 

 Court Road on the south, and Hertford on the north. 



Ireland 



South.—" The Dingle Feds," or " Glengariff'Grits and Slates," 

 lying conformably on the Upper Sdm-ian bed*, as seen in the 

 coast of the Dingle promontory, and overlaid unconformably by 

 either Old Red Sand-tone, or Lower Carboniferous beds, 10,000 

 to 12,000 feet in thickness. 



Afe-M.— "The Fintona Beds," occupying large tracts of 

 Londonderry, Monaghan, and Tyrone, resting unconformably 

 on the Low er Silurian beds of Pomeroy, and overlaid uncon- 

 formably by the Old Red Sandstone, or Lower Carboniferous 

 beds, 5000 to 6000 feet in thickness. 



