124 



J.B. RICHARDSON, R.M. RODRIGUEZ AND S.J.E. SUTHERLAND 



LA PERAL 



ARGOVEJO 



[^:jrEC-;x 



"MN(na) 



■ Shale 





r~t Red Sandstone 



□ Sandstone 





Doiomtte 



[^ Sandstone & Shale 





Limestones 



^ Sandstone /Oolites 





H Ouartzites 



^ Ferrous Oolites 



*JK 



-^ Phosphatic nodules / Clasts 



— — Spore z«nal ho 



undii 



ry 



Silurian /Dc 



vuni 



an boundary based on Chitinozoa 



— P — p — Pridoli Stage 



bou 



ndar> based on chitinozuans data 



SriAGES 



?Hom. 



Fig. 6 Correlation of Cantabrian sections. Spore zonation new, except for LP Biozones after Richardson & McGregor (1986). MN Biozone after Holland 

 & Richardson ( 1977) and Richardson & McGregor ( 1986), and BV Biozone after Burgess & Richardson (1995); MN: micromatus - newportensis, (na): 

 newportensis - argovejae Subzone, (a): Aneurospora Subzone, EC: elegans - cantabrica, H: hemi.sphaerica. RS: reticulata - sanpetrensis, LP: libycus - 

 polymorpha. BV: brevicosta - verrucatus, V: vetusta. Key Cantabrian chitinozoan taxa: Ac: Angochitina chliipaci Lochkovian. Ae: Angochitina echinata 

 Mid Gorstian - Lower Pfi'dolf, AI: Ancyrochitina libyensis Late Gorstian? - Lower Pvridoli, Ath: Angochitina thadeui Lower Gorstian-Late Ludfordian. 

 At: Angochitina tsegelnnki Lochkovian, Cb: Cyathochitina sp. B Late Llandovery, Cr: Conochitina nidda Late Homerian-Lower Ludfordian, Eb: 

 Eisenackitina bohemica Lochkovian, Me: Margachititia elegans Mid Pi'idolf. Pc: Pseitdoclathrochitina carmenchui Mid Pfi'doli, Rv: Ramochitina villosa 

 Late Ludfordian, Ss: Sphaemchitina sphaemcephala Mid Gorstian to Lower PiTdoli, S: Spinachitina sp. Llandovery?, Uu: Umachitina iirna Pfidoli- 

 earliest Lochkovian. 



Artemopyra brevicosta - Hispanaediscus verrucatus (BV) Spore 

 Biozone (Burgess & Richardson 1995). Both the nominal species 

 are found in samples LP3 and LP5. The fact that Hispanaediscus 

 lamontii also occurs in the latter sample may indicate that the 

 junction between the A. brevicosta and H. lamontii Sub-Biozones 

 lies between these two samples. In south Wales this sub-zonal 

 boundary occurs in the Middle Homerian between the liindgreni and 

 nassa Graptolite Biozones. 



Chelinospora reticulata - C. sanpetrensis (RS) Spore Biozone. 



This biozone is represented in all four sections. In the La Peral 

 section both the nominal species appear together in sample LP6. 

 Neither species has been found in the type area of England and 

 Wales. However, the RS assemblages include Concentricosisporites 

 Sagittarius and Stellatisporites inframnrinatus van cambrensis first 

 found in the Lower and lower Upper Gorstian respectively, and 

 spores similar to Chelinospora obscura in the Middle Gorstian. All 

 of these species can occur together in the lower part of the cambrensis 

 Sub-Biozone. On current data, therefore, we tentatively, regard the 

 lower boundary of the RS Biozone as lower Upper Gorstian, approxi- 

 mately lower incipiens Graptolite Biozone. 



Chelinospora hemiesferica (H) Spore Biozone. The base of the 



hemiesferica Biozone is found in sample LP 10 in the La Peral 

 section. Associated spores are mainly found in the Cantabrian Moun- 

 tains and North Africa. Several species, however, also occur in the 

 Anglo- Welsh area. One of these, Chelinospora poecilomorpha occurs 

 throughout the Ludlow Series in south Wales but has not been found 

 in the Lower Pridoli there. In North Africa this species has a similar 

 range and occurs with Emphanisporites splendens, a co-occurrence 

 also found in LP9. In sample LP 1 2 Amicosporites splendidus occurs 

 and this species is also found in the uppermost Ludfordian to 

 Downtonian (Lower Ph'doli) in England but is rare there. The base of 

 the biozone is placed tentatively, therefore, in the Lower Ph'doli but 

 could be also of latest Ludfordian age. 



Scylaspora elegans -Iberoespora cantabrica (EC) Spore Biozone. 



The first appearance of Scylaspora elegans occurs in the La Peral 

 section in sample LP 16 coeval with chitinozoans typical of the 

 Middle Pfi'dolf. This is consistent with chitinozoan finds in the 

 sections of Argovejo (Arg 8), Geras (Ger 10), and La Vid (LV 10, LV 

 II). The base of the zone is therefore placed in the Middle Pfi'doli 

 with some confidence. 



Aneurospora (A) Spore Sub-Biozone. The first occurrence of this 

 genus is found in three of the four sections studied: La Peral (sample 



