The foraminiferal sandy limestones of this series are seen at points in the desert bounding the eastern margin of the cultivation, notably east of Sersena and at the top of the hill 15 kilometres north-east of Rubiat.

The following section was measured at the prominent hills 17 kilometres 28° N. of E. (magn.) of Tamia:—

Metres.
1.Greyish laminated sandy clays withgypsum; Ostrea band near top7
2.White sandy limestone with numerous badlypreserved Ostrea, Pecten, and otherlamellibranchs1
3.Dark-brown clayey sands with gypsum andgrey sandy clays with obscure plant-remains. OccasionalOstrea14
4.Hard, white, sandy limestone withnumerous Ostrea at top; soft clays with gypsum1
5.Greenish and brownish sands and sandyclays with band of sandy limestone near top⎱
⎰		14
6.Greyish-brown, impure, sandy limestoneweathering into large globular concretions. Shell impressions
7.Sandy clays and marls alternating withimpure limestones; much gypsum. Occasional fish-remains and smalloysters⎱
⎰		22
8.Greenish sandy limestone with traces ofshells
9.Finely laminated grey-brown clays withblack carbonaceous matter and fish-remains; saliferous3
10.White sandy limestone1
11.Soft yellow sandstones, etc.⎱
⎰		7
12.White marls with fish-scales, etc.; basenot seen. (This bed, and possibly also 9, 10, 11, should bereckoned as belonging to the Ravine beds)
Total thickness70

In the north of the Fayûm the series is characterized by the presence of one or more very constant well-marked beds of hard calcareous sandstone, which almost invariably weather into huge globular masses. These masses should be regarded as huge weathered-out concretions, rather than as water-rounded blocks, although no doubt in many cases their roundness has been increased by the action of the waters of Lake Moeris as the level of the latter gradually fell, and possibly still earlier during the invasion of the Pliocene sea; from the latter time also may date the millions of parallel vertical borings with which these and other exposed rocks are often perforated. In the various places where one of these beds forms the present surface of the desert the concretions may be seen in different stages of exposure, from the initial, where only just the tops are laid bare, to the final stage where the globes are left completely weathered out, as seen in the illustration ([Plate VII]). The appearance of the desert when covered for many square kilometres with thousands of these blocks is more easily imagined than described.

The lower beds of the Birket el Qurûn series form the island Geziret el Qorn, and consist of clays and sandstones containing a considerable number of organic remains. These beds were collected from and examined by Schweinfurth[44] in 1879, the mollusca being subsequently described by Mayer-Eymar,[45] while the vertebrate remains, which included cetacean bones and numerous fish-teeth, were submitted to Dames.

The following species were determined by Mayer-Eymar, who indicated that the fauna as a whole had a Bartonian aspect[46]:—

Upper Bed.

Lower Bed.