The alternative to Black Ven is to explore the Ammonite Pavement on Monmouth Beach. This is much easier to reach with small children as you can go most of the way on concrete. Tides are also much better as you will not get cut off so long as you do not venture past the headland. There is always something to see, even as you approach high tide. But you still need to be safety conscious and keep well clear of the unstable cliffs and avoid seaweed encrusted surfaces.
To reach the pavement, head west along the seafront. Go past the Cobb harbour on to Monmouth Beach and keep walking for about 400 metres.
The main attraction is the bed of limestone encrusted with hundreds of giant ammonites. There are also loose blocks dotted around containing really big ammonites up to a metre in diameter. The gravel around the pavement contains smaller fossils that can be collected and taken home.