Thanks John. I pass these and many other shells after parking the car on route to the quay. I'd recommend a touristy seaside town,
Not sure where you are but if that is more than a tank of petrol (gas) e-bay has some nice ones.
I do know beaches where there are short stretches and shells collect. Slightly odd but the tide and waves seems to shift and drop them as if sieving them out from the sand .