268 PKOCEEDINGS OP THE GEOLOGICAL SOCIETY. [Feb. 5, 



described by me twenty years ago. These, however, I had not 

 associated with one fault, as it is not uncommon in districts familiar 

 to me to find beds near the brow of an escarpment much dislocated 

 and their levels disturbed. 



I have stated that the Upper Lias Clay, capped by the North- 

 ampton Sand, occurs at a considerable elevation south of Stamford, 

 quite overtopping the town. The effect of the forces producing this 

 fault, whilst probably elevating the beds which appear at so high a 

 level, was to depress other beds throughout a considerable area. 



Thus, at Stamford Bridge, the Upper Lias Clay is only just up to 

 the level of the bed of the river ; and in ascending the hill from this 

 point through St. Martin's, will be passed over in succession — the 

 Ferruginous beds of the Northampton Sand, the Lower Estuarine 

 sands and clays, the Colly weston Slate and Lincolnshire Limestone 

 beds, and the Upper Estuarine Clays; then again, in reiterated 

 sequence, a great thickness of Upper Lias Clay, the Eerruginous 

 beds (worked for ironstone at the top of the hill), the Lower Estua- 

 rine beds, the Collyweston Slate, and further on the rock beds of 

 the Lincolnshire Limestone. So that the Collyweston Slate occurs 

 both at the foot and at the top of the escarpment, with a difference 

 of level of some 150 feet. (See Plate X. fig. 1.) 



A cross fault has divided the sunken mass ; for, in a section at 

 the back of the Midland Railway Station (levelled out of the side of 

 the hill), the Lincolnshire Limestone is seen in lateral juxtaposition 

 with the Ferruginous beds of the Northampton Sand. From an 

 excavation in the Station-yard, I obtained, from a calcareous band 

 in the latter, fragments of a zone containing numerous bivalves, the 

 hollows of which being filled with calcite offer a sparkling contrast 

 to the ferruginous matrix — an effect exactly paralleled by the 

 Astarte-elegans zone in ironstone quarries at Harlestone, near North- 

 ampton. 



The railway passes, by a tunnel under St. Martin's, through the 

 subsided mass of Lincolnshire Limestone, the beds of which have 

 preserved their horizontal position, with little apparent disturbance. 

 At the east end of the tunnel, the railway (very little above the 

 level of the river) passes over beds of the Collyweston Slate ; from 

 which, at this point, in 1853, I obtained the beautiful and unique 

 Astropecten Cottesivoldice, var. Stamfordensis, described, named, and 

 figured, by Dr. Wright, in his Monograph upon the Asteroidea, pub- 

 lished in the volume of the Pakeontographical Society for 1862. 



Bxtkghlet Pake. 



A mile east of Stamford, on the road to Pilsgate, a view of 

 Burghley House, the palatial residence of the Marquis of Exeter, is 

 obtained through the vista of a fine avenue of trees. In the low 

 intervening ground, a few years ago, a temporary excavation ex- 

 posed a section, to the depth of 15 feet, in horizontal beds of the 

 Lincolnshire Limestone. At a higher elevation, the House itself, 

 and the almost encircling ornamental sheet of water, are situated 

 upon the clay of the Upper Lias : the ground still rises beyond, and 



