THE CORALLIAN ROCKS OF ENGLAND. 277 



No sign of any sandy or grit beds can here be discovered below 

 this. 



Before drawing attention to the peculiarities of these strata and 

 their relation to others, it will be well to complete the section of 

 the Corallian beds in this immediate neighbourhood, as we are 

 enabled to do by various minor exposures. The first is seen on the 

 surface of a path on the south of the river leading down to a water- 

 mill. After having here traced the beds down to the loose pisolite 

 (No. 6 a), we find about 12 feet of rubbly creamy oolite under- 

 lying it, easily distinguished from the oolite above. This doubtless 

 takes the place of No. 6 6 ; and beneath it immediately comes stifT 

 blue clay, below which no surface indications are seen ; and the 

 only representative of any thing like grit that we could hear of was 

 met with in the bottom of wells. The "Lower Calcareous Grit," 

 as marked on the map, must therefore here be very feeble indeed. 



Not far from this spot, on the highroad- side, are some other 

 exposures, serving to show the variable nature of No. 5, as in one 

 place it is only 10 feet thick, and a little further to the west 

 thins out altogether, and .the lower marls, here crowded with 

 Echinobrissus scutatus, are in contact with the rubbly beds, which 

 are more argillaceous. 



On the roadside to the east of the bridge are seen rough, shelly, 

 thin-bedded limestones, dipping east at about 5°, which represent the 

 base of No. 3 ; and these are followed in the direction of the dip, as 

 seen in a quarry, by more creamy shelly limestones, with abun- 

 dance of Natica, Nerincea, &c, which have a thickness of at least 

 12 feet, and represent therefore a larger develojDinent of calcareous 

 matter in this part of the section than is seen in the railway-cutting. 

 Above these, in the Hole road, we meet again with the clays and 

 sands of the railway-section ; but above them we find ferru- 

 ginous fossiliferous sands and concretions, which form a rock 

 mass at the top, and are succeeded by broken Kimmeridge Clay. 

 The fossils of these beds are Ammonites plicatilis (?), Bdemnites 

 nitidus, Pleuromya tellina, Pinna pesolina, Pecten midas, Avicida 

 cedilignensis, Ostrea deltoidea, Serpula runcinata. This completes 

 the series ; and we may anticipate so far as to say that the 

 characters here exhibited are, with minor exceptions, fairly typical 

 of the whole region of North Dorset. 



We first remark here the feeble development of the grits and 

 sands at the base, which usually form so marked a feature. They 

 are hardly to be discovered at all at Sturminster ; and to the south of 

 the town, along the westerly range, we have but very slight indi- 

 cations of occasional grits. As we pass north, however, they . 

 become of slightly more importance, and at Cucklington form part 

 of a somewhat steep escarpment. In the neighbourhood of Marn- 

 hull and Stower Provost also grit beds of some thickness occur ; 

 and at the eastern entrance to the Gillingham tunnel a good 

 section appears, which, as it is the only one in this district, we give 

 in descending order. 



