ON THE FORMATION OF ‘ ROSTRO-CARINATE’ FLINTS. 789 
over the surface of the Bracklesham Clay, and closely associated with 
them are the well-known erratics of the southern drift. The former 
action of floating ice on these erratics, which has driven them forcibly 
into the underlying clay and sometimes crushed them to fragments, 
has been pointed out by Mr. Clement Reid.‘ Flints and erratics form 
together the base of the Pleistocene series as it exists at Selsey, and 
their exposure by the removal of this series under marine erosion is 
of very recent date. 
All the flints of these patches present one or more fractured surfaces 
and some of them bear glacial strie; the fractures, as shown by their 
patination, are of very different ages, but there is nothing to show that 
they have been produced by actions of more than one category. The 
deposit does not suggest a paleolithic or eolithic floor; it has all the 
characters of a geological formation. 
The rostro-carinate form is very simple and may be produced by 
chance blows. It arises whenever an elongated mass of flint—a nodule 
or a fragment already blocked out by joints—is traversed by two sur- 
faces of fracture which are inclined in opposite directions and converge 
so as to intersect along a line (carina). 
Fragments fulfilling one or other or all of these conditions are to 
be met with on the Selsey beach, and they present a variety which is 
suggestive of chance rather than design. When the rostro-carinate 
form is attained it sometimes exhibits a ‘ ventral’ flaking, but this, as 
in the examples from the Red Crag, is an inconstant character. 
Among the most interesting flints at Selsey are some large irregular 
nodules with elongated rounded processes running out from them. 
These processes have been battered by the waves and have yielded in 
the same way as the simple nodules which have been converted into the 
rostro-carinate form. They are broken along surfaces which sometimes 
do and sometimes do not intersect; when they do a rostro-carinate 
form is produced, and this projects from the side of the ill-shaped 
nodule in a manner as difficult to associate with design as it is easy to 
interpret by the action of known natural causes. 
From these nodules it is but a step to the ‘ paramoudras’ of the 
Norfolk coast, which present similar processes similarly battered, but 
attain such dimensions that no single man unaided could lift one from 
its bed. 
The flaking of the Selsey ‘ rostro-carinates ’ is as interesting as their 
form. Some are bounded by flaked surfaces having all the same kind 
- of patination and therefore produced during one and the same 
geological epoch, but there are others in which these surfaces are 
distinguished by widely differing patinas, so that their existing form is 
the result of blows struck at widely separated periods, some during the 
Pleistocene and some during the recent epoch. . The Abbé Breuil 
considers that some of the facets on the sub-Crag examples have been 
produced at different times. 
Some of the most ancient of the uniformly patinated examples show 
* Clement Reid, ‘ The Pleistocene Deposits of the Sussex Coast,’ Quart. Journ. 
Geol. Soc., 1892, vol. xlviii., pp. 344-64, in particular p. 3650. 
