280 Revieius^Geology of Fareham and Havant. 



of Heteroceras reussiammi has not been recognized, and the Chalk 

 Rock often developed at that horizon is wanting. Little is seen of 

 the zone of Micraster cor-testudinarium. Mr. Brydone's estimate of 

 the combined thickness of the Cor-tediidinarium and planus zones at 

 "Waruford is 1 12 feet. The zone of Micraster cor-anguinum is 226 feet 

 thick at Warnford, and consists mainly of soft white chalk with 

 abundant flints. There are few exposures, as is also the ease in the 

 Marsupites testudinarius zone. The chalk of this zone is very soft 

 and contains few flints. The Uintacrinus and Marsupites bands are 

 both recognizable, and each is probably about 35 to 40 feet thick. 

 The zones of Actinocamax quadratus and Belemnitella mucro7iata are 

 well exposed. The former is about 300 feet thick ; in its lower part 

 it is soft white chalk very similar to that of the underlying zone ; it 

 becomes gradually more marly and contains an increasing number of 

 flints towards the top ; all the exposures of consequence are in Ports- 

 down. Details are given of the subdivisions of this zone advocated 

 by Messrs. Griffith and Brydone. The zone of Belenmitella mucroiiata 

 is well developed near Fareham, where there appears to be a thickness 

 of about 60 to 70 feet. 



The Memoir deals in detail with the various exposures of the 

 several zones, and an extensive zonal list of fossils is given. The 

 junction of the Cretaceous with the Eocene beds is nowhere clearly 

 shown, but their uuconformability is proved by the relations of their 

 outcrops in different parts of the district. The mucronata beds of 

 Portsdown have nowhere been observed along the northern boundary 

 of the Eocene strata between Upham and Euntington. This discordance 

 is part of a widespread unconformity which takes the form of an 

 overstep of the Cretaceous by the Eocene in a northward direction ; 

 thus more than half the Upper Chalk is cut out in the distance of 

 50 miles between the Isle of Wight and the Berkshire Downs. 



The Eocene beds immediately overlying the Chalk belong to the 

 Reading Series; the seams of glauconitic sand which are common 

 in other areas are found to be wanting, as also are the commonly 

 associated oyster-shells and fish-teeth. The bulk of the formation 

 consists of clays and loams. The average thickness is estimated at 

 about 110 feet. Notes are given of exposures in both the northern 

 and southern outcrop. 



The thickness of the London Clay is given at about 250 feet. It is 

 made up of evenly stratified silty clays, loams, and loamy sand, with 

 thin beds or seams of impure shelly limestone and of flint pebbles. 



Details of sections are given and a list of fossils from the Catis- 

 field cutting and from Eareham Station. Short chapters deal with 

 the Bagshot Sands and Bracklesham Beds ; the thickness of both 

 varies considerably. A chapter on Tectonic Structure and Land 

 Forms is of considerable interest. It is considered that during the 

 Eocene and Oligocene periods the eastern part of the Hampshire Basin 

 never rose much above sea-level, the main folds being developed in 

 Miocene times, and the various folds and faults are discussed in 

 detail. A few interesting points in connexion with the drainage of 

 the country are also brought forward. A number of unstratified 

 superficial deposits are grouped under the heading of Clay-with-Flints; 



