The incident happened yesterday between 2.15pm and 3.25pm in Lollesworth Lane near the railway bridge.
A man in his 20s has been arrested on suspicion of attempted rape and common assault.
Surrey police says visitors to the beauty spot will notice an increased officer presence while they carry out investigations.
Statement from Surrey Police.
We are looking to speak to anyone who might have been in the area around Lollesworth Lane between 2.15pm and 3.25pm yesterday afternoon and who might have seen anything suspicious during this time.
If you have any information that may assist our investigation, including CCTV, dash cam or helmet cam footage, please get in touch quoting PR/45240054293 via:
Webchat on our website https://www.surrey.police.uk/
Our online reporting tool https://www.surrey.police.uk/tua/tell-us-about/cor/tell-us-about-existing-case-report/
Calling us on 101.
If you do not wish to speak to police, you can call independent charity Crimestoppers on 0800 555 111.
