26 THE CAMBRIAN AND ORDOVICIAN DEPOSITS OF MARYLAND 



those of the Lower Silurian, an opinion eminently correct because, as just 

 noted, he had included in it all of the fossiliferous Cambrian. In the 

 publication of his Siluria several years later, Murchison still regarded 

 Sedgwick's Cambrian system as simply a local facies of the Silurian 

 system. The historic but unfortunate controversy on this question now 

 ensued. Murchison, by means of his influential official and social position, 

 was able to dominate the subject and most of the rocks now recognized 

 as Cambrian, Ordovician, and Silurian were marked Silurian on the 

 British geological maps, and in both America and Europe fossils collected 

 from the equivalent of the " Transition Series " were almost invariably 

 classed as Silurian. The term Cambrian was practically discarded 

 because, according to Murchison, it was impossible to recognize the strata 

 on account of their supposed lack of characteristic fossils. 



Tn 1879 Professor Lapworth of Birmingham University, England, 

 proposed that Murchison's term Lower Silurian be replaced by the name 

 Ordovician, after the Ordovices, a tribe which lived in Wales at the time 

 of the Romans. Sedgwick in his writings continued to insist that the 

 Cambrian system was an independent group of rocks and proposed to 

 limit the Silurian to the Ludlow and the Wenlock, with the Mayhill sand- 

 stone at the base. In his introduction to Salter's Catalogue of Cambrian 

 and Silurian fossils, published in 1873, the year of his death, he held to 

 this same view. As practically all of the faunas which he" considered as 

 Cambrian and the main mass of the rocks included by him in the Cam- 

 brian system are now recognized as typical Ordovician, it is evident that 

 the present-day usage of the term Cambrian does not follow the intentions 

 of its author. The upper, typical portion of the Silurian system, to 

 which the name Silurian was restricted when Lapworth introduced the 

 new name Ordovician for the Lower Silurian, was named Murchisonian 

 by d'Orbigny in 1850, but this term never received a wide acceptance. 



With the adoption of the terms Ordovician and Silurian by many 

 geologists the name Cambrian was finally retained for the lower, much 

 more sparingly, unfossiliferous rocks of the original Cambrian of Sedg- 

 wick a most unfair procedure and one to which that author objected 



