384 CAMBRIAN AND SILURIAN IN EUROPE. [XV. 



more or less cupriferous, and themselves also contain gold-bear- 

 ing quartz veins. (Mem. Geol. Survey, Pail II. pages 42, 45 ; 

 and Siluria, 4th ed. 450, 547.) 



The Table on page 386 gives a view of the lower palaeozoic 

 rocks of Great Britain and North America, together with the 

 various nomenclatures and classifications referred to in the pre- 

 ceding pages. In the second column, the horizontal black 

 lines indicate the positions of the three important palseontologi- 

 cal and stratigraphical breaks signalized by Ramsay in the 

 British succession. (Mem. Geol. Survey, III. Part II. page 2.) 



[Very recently, in 1873, in the Proceedings of the Geolo- 

 gists' Association, Vol. III. Part III., Mr. Hicks has given a 

 similar tabular view of the lower palaeozoic rocks of Great Brit- 

 ain. The Bangor group (to which he applies the name of Long- 

 mynd or Lower Cambrian),differs from that given in the follow- 

 ing table only in dividing the Menevian into an upper and a 

 lower part. The Middle Cambrian or Festiniog group of Sedg- 

 wick (which Hicks calls Upper Cambrian) presents also the 

 same subdivisions as are here given. In the next, or Upper 

 Cambrian of Sedgwick (called by Hicks Lower Silurian), are in- 

 cluded in ascending order Lower Arenig and Upper Arenig or 

 Skiddaw, followed by Llandeilo, also divided into two parts, 

 and by the Bala group, which he divides into Lower and 

 Upper Caradoc, to which he adds, as we have done, the Lower 

 Llandovery.] 



[In the new Catalogue of the Cambridge Fossils is an impor- 

 tant preface written from Sedgwick's dictation late in 1872, 

 and published since his death. In this he unites the Lower 

 Llandovery with the Upper Cambrian, and includes it, together 

 with the Caradoc and Llandeilo, under the name of the Rila 

 group, which he divides into Lower, Middle, and Upper Bala ; 

 while the Arenig or Skiddaw rocks are joined with tho 

 Mi<ldle Cambrian. Both the Arenig and the Tremadoc rocks, 

 in fact, present a certain intermingling of organic forms belong- 

 ing to the first and second faunas ; but according to Hicks tho 

 Tremadoc beds are to be classed with the first, and the Arenig 

 with the second. These two groups of rocks are in fact the 



