G6 



HARDWICKE'S SCIEN CE- GOS SIP. 



they lie, and by the intercalation among them of 

 old soils, forests, mud-streams, river-gravels, lake 

 deposits, and musses of unstratified tufTs and ashes. 

 From the analogy of existing volcanic districts, we 

 can scarcely doubt that these great accumulations 

 of igneous products, which must originally have 

 covered many thousands of square miles, and which 

 still often exhibit a thickness of 2,000 feet, were 

 ejected from great volcanic mountains ; and a care- 

 ful study of the district fully confirms this con- 

 clusion, enabling us, indeed, to determine the sites 

 of these old volcanoes, to estimate their dimeusious, 

 to investigate their internal structure, and to trace 

 the history of their formation. The following is Mr. 

 Judd's conclusion on his paper: — It appears that during 

 the Newer Palaeozoic and the Tertiary periods, the 

 north-western parts of the British Archipelago were 

 tiie scene of displays of volcanic activity upon the 

 grandest scale. During either of these, the erup- 

 tion of felspathic lavas, &c., preceded, as a whole, 

 that of the basaltic ; and in both the volcanic action 

 was brought to a close by the formation of "puys." 

 Tlie range of Newer Palaeozoic volcanoes arose 

 along a line striking N.E. and S.W. ; that of the 

 Tertiary volcanoes along one striking from N. to S. ; 

 and each appears to have been connected with a 

 great system of subterranean disturbance. It is an 

 interesting circumstance that the epochs of maxi- 

 mum volcanic activity, the Old Eed sandstone and 

 the Miocene, appear to have been coincident with 

 those which, as shown by Prof. Ramsay, were cha- 

 racterized by the greatest extent of continental land 

 in the area. The Secondary strata were deposited 

 in the interval between the two epochs of volcanic 

 activity, and the features which they present have 

 been largely influenced by this circumstance. 

 Apart from this consideration, however, the vol- 

 canic rocks of the Highlands are of the highest 

 interest to the geologist, both from their enabling 

 him to decipher to so great an extent the " geolo- 

 gical records " of the district, and from the light 

 which they throw upon some of the obscurest pro- 

 blems of physical geology. 



The Geology of the "Ear "West."— Prof. 

 Marsh has just communicated tlie results of his 

 recent expedition to the Ear 'West in search of 

 fossil remains of extinct vertebrates. The richest 

 field for exploration was found in the great basin of 

 the pre-historic lake which is now drained by the Colo- 

 rado river. This body of water was originally as large 

 as all the present lakes of the North- West combined, 

 and had existed so long that the sand washed down 

 from the surrounding hills had accumulated to the 

 depth of a mile. In the different strata of this bed 

 at least ten distinct groups of extinct animals could 

 be detected, among them some extremely remark, 

 able forms. One of these was a rhinoceros with 

 two horns ; but these were placed, not like those 



of the modern rhinoceros, in the axis of the body 

 but transversely. In a space of 10 feet square he 

 had sometimes found the bones of 30 different ani- 

 mals. Tue number of species of extinct mammals 

 in these remains he estimates to be three times as 

 great as that at present inhabiting the same locality. 



Pal^othebium magnuh. — In Nature of the 12th 

 February is an account of the discovery of a com- 

 plete skeleton of this early eocene mammal. The 

 woodcut shows its outline to more nearly resemble 

 that of the Llama than any other known creature ; 

 thus completely disabusing the old Cuvierian idea 

 that it was bulky, and more or less resembled the 

 Tapirs. The height was just below that of a middle- 

 sized horse. This important specimen, which is 

 now in the Museum of Natural History at Paris, 

 was obtained from a gypsum quarry at Vitry-sur- 

 Seine. All its bones, including those of the toes, 

 are in their natural position. 



The Origin of Precious Stones. — Mr. Gre- 

 ville WiUiams has recently contributed his re- 

 searches on this interesting subject to the Proceed- 

 ings of the Royal Society. The colouring matter 

 of the emerald has been attributed to iron, chro- 

 mium, and organic matter. With regard to the 

 latter, Mr. Williams thinks that both emeralds and 

 beryls contain carbon ; but that it is probably in the 

 form of diamond, and has nothing to do with the 

 colour of the emerald, as colourless beryls may con- 

 tain as much carbon as the richest tinted emerald. 

 The colour is really due to the presence of chromic 

 oxide. ]\Ir. Williams then gives the results of his 

 experiments on the effects of fusion on opaque 

 beryls, emeralds, and an artificial mixture of beryl 

 ingredients. The author expresses his opinion that 

 whatever may have been the temperature at which 

 beryls and emeralds were formed, rubies must have 

 originated at a very high temperature, since the 

 peculiar reaction between alumina and chromic 

 oxide, to which the red colour of the ruby is due, 

 takes place only at a heat as high as that of the oxy- 

 hydrogen flame. 



A NEW Species of Fish in the j\Iillstone 

 Grit of Yorkshire. — At the monthly meeting of 

 the Manchester Geological Society, held on the 27th 

 of January last, Mr. John Aitkin, F.G.S., of Bacup, 

 exhibited and described a number of very fine 

 spennens of fish of the genus Acrolepis, new to 

 science, which he had obtained from the debris 

 brought out in excavating a tunnel through Wads- 

 worth Moor, in the neighbourhood of Hebdea 

 Bridge, near Halifax, in a bed of fine black shale 

 separating the third from the fourth or Kinder 

 Scout Grit; the principal specimens having been 

 obtained from nodular concretions which abound in 

 the shales at this horizon. The specimens com- 

 prise two nearly perfect heads (in the jaw of one a 



