Seashells in situ on Swansea Bay strandlines or drift lines are mostly tiny immature common cockle shells but there are many other species of bivalve and gastropod mollusc shells too. I noticed mussels, tellins, and oysters, winkles, top shells, netted whelks, sting winkles, slipper and common limpets, and I am sure there were many more types. There were seven drift lines of shells lying parallel to the water line and decreasing in the number of accumulated shells sequentially up the shore. Each line represents the highest reach of the sea on a series of subsequent falling tides that were decreasing in reach each time.
It was interesting to see that wave-worn pieces of black coal and dark clinker from industrial plants across the bay were scattered amongst the light coloured shells together with a fair number of burial-blackened periwinkles. Many of the shells were fragmented and the accumulations included the calcareous tubes of marine worms. It would be lovely next time to take a sample home and sort it through under a binoc. I am sure that it would reveal much more information.
Click on any image below to see the details in a larger version.
Jessica's Nature Blog 
I have never seen so many seashells. Do they blow in from the sea and end up on the beach? Just seem to be same places they end up on.
LikeLike
Lovely sea shell images….
LikeLike
Thank you, Evelyn.
LikeLike
All the bivalve shells like the baby cockles have been living in the softer muddier sediments lower on the beach and on the seabed further out in the bay. Thy have died out there for some reason and been washed in by the tide.
LikeLiked by 1 person
“Strandline,” “drift line,” thank you for these words. Nice to have names for what I have observed. (Also, thanks for the photographs ;-))
LikeLike
Thank you, Linda.
LikeLike
These are so beautiful! I am visiting Swansea with my daughter and we love to shell collect- would you recommend anywhere particular in the bay for these sorts of finds?
LikeLiked by 1 person
Hi. It is difficult to say which would be the best place to collect seashells at Swansea because it depends on the tides and the weather. But I was in Swansea earlier this week and there were many drifts of shells along the tide lines near to the Council offices and the development around the marinas (at the opposite end of the beach to the Mumbles). It is easy to get down to the beach from the promenade. There are also significant accumulations of shells at the base of the long iron pier-like structure that extends out seawards on the bank of the Tawe estuary at the Swansea end of the beach.
LikeLike
Thankyou so much- I will be sure to look there!
LikeLiked by 1 person