MAUCOU — ON THE NEOCOMIAN AND TUE WBALDEN UOCKS. 
5 
(c). The Neuchatel stone, or yellow stone (Fiem Jaime ou Pierre de 
Neuchatel), sixty feet thick, is the beautiful material which gives to 
the buildings of the town of Neuchatel that clear yellow colour so 
much admired by travellers. Fossils are rare in this division, and 
never in a good state of preservation. Typical localities : vicinity of 
Neuchatel and Pontarlier. 
The Upper Neocomian, or Noirvaux, group is well developed in the 
Noirvaux valley near St. Croix ; it is this group, or rather the 
fauna contained in its strata, that D'Orbigny has called Urgonian. 
Two divisions are generally found in it ; (a) the Mauremont rocks, 
and (')) the Noirvaux-Dessus Limestone. 
(a). The Mauremont rocks {Roches du Mauremont), forty feet thick, 
consist of yellow limestone, very difficult to distinguish from the divi- 
sion below ; they become marly, and finally terminate with a bed of 
yePow marls containing numerous fossils. The characteristic fossils 
are : Janira atava, D'Orb. ; Toxa&ter Couloni, Camp. ; Pygurus pro- 
ductus, Agass. ; Cidaris clunifera, Agass. ; Caprotina Duhuisii, Mer. ; 
Rhynchonella lata, D'Orb., &c. Typical localities : Mauremont in 
the Canton de Vaud ; St. Croix, Travers, Bole, &c. 
('/). The Noirvaux-Dessus Limestone {Calcaires de Noirvaux-Dessus), 
one hundred and ten feet thick, has been often called the Caprotine 
Limestone ; it is a series of beautiful white and sometimes yellow 
limestcnes, affording a marble much employed at Thoiry, near Geneva. 
Characteristic fossils : Caprotina ammonia, D'Orb., and Eadiolites Neoco- 
miensls, D'Orb. Tyj.ical localities : Noirvaux-Dessus, near St. Croix, 
Thoiry, Les Rousses, &c.* 
The strata of the Greensaud formation lie directly above the 
Neocomian and in concordance of stratification. Eugene Renevier, 
who has made a special and very successful study of the Greensands 
in England and at the Perte du Rhone, considers the lower Perna- 
bed, containing the Natica rotundata, Sow., &c., of the Lower Green- 
sand of the Isle of Wight, to be the equivalent of the yellow clay 
{Marnes jaunes) cjutaining Natica rotundata, Sow., (fee, of his 
Rhodanian group of the Greensands of the Perte du Rhone. 
* For a more detailed account of the Neocomian Strata, see Sur le Neocomien 
dans le Jura et son rdle dans la serie slratigrajihique, by Jules Marcou. 
Geneve, 1859. 
