Geologists' Association. 471 



these marly cream-coloured rocks much better huntmg ground than the sandy, 

 irony, and calciferous beds which go to make up the Northampton Sand of the 

 Inferior Oolite. Rhynclionella concinna, Modiola imbricata, Myacites calceifot'mis^ 

 Ostrea Soiverbyi, were to be picked up in abundance. Besides these, specimens of 

 Clypeus Mulleii, the characteristic Pinna ampla, Myopsis dilatatus (stunted speci- 

 men), Isocardia teneta, and several others, were obtained. Mr. Sharp pointed out 

 also a hard semi-crystalline bed, crowded with Alaria, Nerincea, Astarte, and 

 other shells, but in such a matrix as to defy extraction without time and proper 

 appliances. 



Descending eastwards, the Broughton Green Quany was visited, where, as in 

 the Nursery Pit previously noticed, the base of the Northampton Sand appears as 

 a limestone more or less sandy, and not obviously fossiliferous. Indeed up to this 

 point not a fossil had been secured by any of the party from the Northampton 

 Sand as evidence of its geological horizon. At Bass Pit, however, nearer North- 

 ampton, a single specimen of the very characteristic Rhynchonella cynocephala 

 was secured. Yet, by watching carefully, Mr. Sharp has obtained from these pits 

 and elsewhere, a large series, in species more numerous than has been obtained 

 from the much more fossiliferous Great Oolite above. 



This completed the inspection on the north side of the town, through which the 

 party now passed out towards the west, making a pilgrimage en passant to the 

 tomb of William Smith, "the Father of English Geology," who, whilst journey- 

 ing to a meeting of the British Association, was in this town arrested by death, 

 28th August, 1839, and buried in St. Peter's churchyard. 



The Duston Quarries presented the most imposing section of the ironstone series 

 of " the Northampton Sand" visited during the excursion, having 22 feet of iron- 

 stone alone. Amongst the few fossils secured were Pecten personatus^wdi. Gervillia 

 Harti7ianni ; but, as in all other quarries of this stone, there were very few to be 

 found. Mr. Sharp's collection, however, is so rich as to supply all that is required 

 for reading the life history of the period to which these beds must be assigned. 

 The majority of fossils from this place occur as casts. Judging from data thus 

 supplied, there can be very little doubt that these beds belong to the Inferior 

 Oolite, and to the lowest zone of that formation, as might indeed have been 

 inferred from their resting immediately on the Upper Lias clay. It is not quite 

 clear whether the passage or Opalinus beds should be included ; but as Am7tionites 

 Miirchisona: occurs tolerably high up in the ironstone, this is at least probable, and 

 many other facts, such as the occurrence oi Rhynchonella cynocephala, point in the 

 same direction. Cardium Buckma7tni, Pholadomya fidicida, Ceromya Bajociana, 

 Isocardia cordaia, Terebratula ovoides ( T. trilineata of Young and Bird), and 

 numerous species of Li7?ia and Ciicullaa, peculiar to the Inferior Oolite, all tend to 

 prove the true position of the ironstone, which, indeed, could never have been 

 assigned to any other formation if the extensive series of fossils obtained since the 

 working of these numerous quarries had been available at an earlier period. 

 Their resemblance in many respects to the " Dogger" of North-East Yorkshire 

 is most remarkable, as was some time ago pointed out to Mr. Sharp by Dr. Lycett. 

 This latter fact suggests many reflections as to the original condition and sub- 

 sequent metamorphism of these very singular beds. At present the bulk of the 

 mass consists of a yellow friable earth, partly sandy and partly Oolitic, seamed 

 in all directions by hard bands, consisting chiefly of hydrous peroxide of iron. 

 This, when sifted, constitutes a considerable portion of the commercial ore, and 

 contains, perhaps, somewhat under 40 per cent, of metallic iron. About 

 1800 tons of it are raised weekly in the Duston Quarries. In some places there 

 occurs a line of nodules of ferrous carbonate, and in the Duston Quarries a very 

 striking feature is a thick band of greyish green ironstone, low down in the series, 

 which is rejected on account of the quantity of phosphoric acid which it contains. 

 This is, for the most part, a carbonate of iron, with, perhaps, some silicate. Such 

 is a very brief outline of the present condition of the beds. That this condition 

 is the result of chemical changes, occurring at more than one period in the history 

 of these rocks, the traces of so many organic remains prove most conclusively. 

 And here a study of the contemporary (in a geological sense) ferruginous Oolites 

 of Yorkshire may help us much. Taking the Dogger Beds at Blue Wyke, we 

 find an arenaceous Oolite, in which there is hardly any lime. The ova there' con- 

 sists almost entirely of ferrous carbonate. It might be contended by those who 



