British Speleological Expedition to the Cantabrian Mountains of Northern Spain, 1965
in conjunction with the "Espeleologos de Penalba", Leon
|British Speleological Expedition 1965 Report|
Entrance in side of stream's bed which is covered in flies, hence the name. 10' crawl leads into rift bedding at 60 degrees. A 10` climb down and short crawl loads to the top of 75' pitch. In wet weather could be very wet as water from stream enters half way down. The bottom of pitch leads to main chamber. The water continuous down small passage and then splits up.
An upper passage which is covered in mud goes to east of rift, leading into small chamber which is same height as entrance.