100 Mr. G. Tate on the Geology of the Howick Coast 



shield are found ; and I havespe- Productus fimbriatus, Sow. 



cimens showing the reticulated Flemingii, Sow. 



structure of the eye of this Trilo- giganteus, Sow. 



bite. semireticulatus, Martin. 



Nucula gibbosa, Flem. Spirifer glaber, Sow. 



Leda attenuata, Flem. trigonalis. Sow. 



Solemya primaiva, Phil. Urii, Flem. 



Chonetes Hardrensis, Phil. Reticularia lineata, M'Coy. 



Lingula elliptica, Phil. Euomphalus carbonarius, Sow. 



marginata, Phil. Murchisonia elongata, Port. 



Orbicula ? quadricarinata, M'Coy. 



Orthis arachuoidea, Phil. Pleurotomaria atomaria, Phil. 



Michelini, Lev. Bellerophon striatus, Flem. 



resupinata, Phil. &c. 



A white flaggy sandstone underlies these calcareous beds, and 

 contains a remarkable vermiform fossil, the nature of which has 

 not yet been satisfactorily determined. 



The limestone and sandstone beds are cut through, nearly 

 perpendicularly, by a small basaltic dike, which runs from the 

 shore into the sea in a perfectly straight direction, east 50° north. 

 It is only 4 feet wide ; but standing above the stratified beds, 

 and appearing like a wall built up by human hands, it is a sin- 

 gular and interesting object. The adjacent beds are not affected 

 by it, either in position or structure. 



Proceeding southward, arenaceous shales with ironstone no- 

 dules, thick beds of blue limestone, and another stratum of "Calp'' 

 rise out from beneath the flaggy sandstone. But nearly opposite 

 to Howick village, these beds are cut off, by a great fault, 

 which has rent the beds and considerably altered their position. 

 This fault " hades " or slopes to the south, and the strata on 

 the north side have been thrown up; it is filled partly with 

 shattered fragments of limestone and calp and with basalt ; it is 

 in fact a small vein containing, mixed with the veinstones, galena 

 or sulphuret of lead. It runs in the direction of east by north ; 

 and as a lead-mine was formerly worked at Little Houghton, 

 both are probably parts of the same vein. This great rent in 

 the earth's surface appears to be the result of the volcanic out- 

 bursts, which threw up from the molten depths, the basalts spread 

 over the eastern part of the district ; for there is a mass of amor- 

 phous basalt in this vein, connected with a stratum of basalt forced 

 in between the limestone and sandstone on the north side of the 

 dike, the sandstone being in a shivered and indurated state. In 

 the basaltic mass, small but fine crystals of quartz, some of them 

 amethystine, have been found. 



On both sides, the beds rise towards the fault ; on the north 

 side the dip is at a high angle to the N.E. ; but on the south side 

 it is E.S.E. The series of beds is also different ; for, on the south 

 side neither the limestone nor the calp appears. From this point 



