104 BRITISH PALASOZOIC SPONGES. 
the limestones only the microscopic detached skeletal-spicules of Sponges have been 
preserved. 
Permian System.—It is doubtful whether any genuine fossil Sponges have as 
yet been discovered in the strata of this system in the British area; those described 
as such by the late Prof. King’ prove, on examination, to be either organisms of 
very problematical character or inorganic concretions. The forms described as 
Sponges by Prof. Geinitz’ from the corresponding Dyas of Germany, are of an 
equally dubious character. 
1 *Monog. of the Permian Fossils,’ Pal. Soc., 1849, pp. 11—14. 
2 «Die animalischen Ueberreste der Dyas,’ 1861, pp. 123-4, pl. xx. 
